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So let's talk about arteriovenous fistula complications. 2 00:00:01,900 --> 00:00:03,500

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So we have a 66-year-old woman, postoperative

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day 3 from cardiac catheterization for a

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radiofrequency ablation to treat her VTAC.

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So now she presents with an audible

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bruit associated with her right

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common femoral arterial puncture site.

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What are you thinking?

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So what diagnostic imaging would you do

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to confirm the diagnosis in question?

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Ultrasound with Doppler?

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Love it.

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So about 33% of arteriovenous fistulas actually resolve

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16 00:00:27,505 --> 00:00:29,395 spontaneously within about a year.

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However, an intervention is often recommended for

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those persisting beyond two months, significantly

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increasing in size, or that become symptomatic.

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So let's proceed.

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So what is a significant

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finding in the ultrasound?

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So an arteriovenous fistula can

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actually be seen on the ultrasound.

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So what are we seeing here?

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A little bit of a communication

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between the artery and the vein.

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So we're going to look at a little better

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example so that you can see what we see as

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an interventionalist when there's a communication.

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But first and foremost, let's define what

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a communication is between an artery and

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a vein, which is an arteriovenous fistula.

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So this is essentially an anomalous

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connection that should not be present

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between an artery and a vein.

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It can often be formed from an infectious insult,

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an iatrogenic or post-traumatic injury,

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in which case now you have an artery

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and a vein communicating because of this

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injury, because of this communication.

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These occur on the order of 0.01%

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44 00:01:32,779 --> 00:01:34,949 to 0.02%, so a little bit on the rarer side

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when compared to things that we've experienced

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and discussed in our conversation today.

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So when they present, almost

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all AVFs are clinically silent.

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The exam may sort of tip you off because you may

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reveal a palpable thrill or an audible bruit.

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So, be very suspicious.

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53 00:01:52,715 --> 00:01:54,184 So what are the risk factors for AV

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fistula that would make you suspicious?

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If you've had multiple puncture attempts,

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you're hitting below the inferior margin of the

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femoral head, where, of course, the vein

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runs posterior to the artery, so helping

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to communicate between the artery and the

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vein, and to sort of bring them together as one.

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Not a good look if you're using a large

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caliber puncture needle, 18 gauge, for example.

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If there's high blood pressure, high pressure,

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double wall puncture below the inferior margin of the

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femoral head, now we've got a nice combination

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therapy to make that AV fistula a reality.

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Not a good look.

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Anticoagulation, antifibrinolytics,

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also not a good look.

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Of course, advanced age is also the other thing

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that would provoke this increased propensity.

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So how do AV fistulas actually

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present on ultrasound?

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Well, high-frequency, low-resistance flow.

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We see this continuous flow and

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elevated diastolic velocities

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throughout the pulse cycle,

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which is what we're seeing here.

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It's almost like a machine murmur that you

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hear, or, sort of, when you're listening to,

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sort of, a patent ductus arteriosus in a child,

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that machine-like continuous murmur. Imagine

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this sort of continuous, this AV fistula,

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sort of machine, sort of action going on here.

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So, as it's challenging to diagnose an AVF,

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an AVF with a grayscale ultrasound, really sort of

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get that color Doppler to sort of be employed,

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and that's going to sort of clinch your diagnosis.

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90 00:03:17,685 --> 00:03:18,964 So what's the management of an AVF?

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You can observe, follow up ultrasound

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in one month, ultrasound-guided

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compression, been there, done that.

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Could we embolize?

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Yeah, of course we could.

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Across the communication, certainly.

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Stent exclusion, okay?

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That can also be, and we would sort of place

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that off the artery so that we can

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ensure that there's no longer communication

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from the high-pressure system, the artery,

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to the low-pressure system, the vein.

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And, if you're a surgeon, you do

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what surgeons do, which is operate.

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And that would also be an option.