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Adrenal Vein Sampling: Tips for Cannulating the Right Adrenal Vein
Rajat Mohanka • Updated Oct 28, 2023 • 174 hits
Adrenal vein sampling can help discern whether a patient with primary hyperaldosteronism should be treated with unilateral adrenalectomy or managed with medications. To minimize harm to the adrenal gland, it is important to rely on visual cues from angiograms for accurate adrenal vein placement, and to ensure safe contrast injections. Additionally, cannulating the right adrenal vein presents a unique set of challenges due to its proximity to the hepatic veins. However, there are a few technical methods that can help to ameliorate these challenges, such as manually modifying the C2 catheter.
Dr. Fritz Angle, an interventional radiologist from University of Virginia, explains how to cannulate the right adrenal vein during adrenal vein sampling, how to confirm accurate placement, and how to ensure safe contrast injections. This article includes excerpts from the BackTable Podcast. The full episode is featured below.
The BackTable Brief
• The C2 Catheter is primarily used for right vein cannulation. The operator can modify the catheter with additional side holes near the tip for ideal placement in the adrenal vein.
• Prioritize gentle injections to prevent over-injecting and potentially causing a venous infarct in the healthy adrenal gland.
• Dr. Angle recommends utilizing a 0.014 wire through the catheter to confirm if it is pointing at the gland or the liver, obviating the need for contrast.
• Look for a triangular or upside-down Y shape with a fine branching pattern in the angiogram to ensure you're in the right adrenal vein.
• Be cautious of branches extending beyond the blush to the hepatic vein or into the retroperitoneum, as they signify wrong placement.
• Utilize stat cortisol levels to confirm correct vein placement when possible, acknowledging the potential delay in modern laboratory settings.
Table of Contents
(1) The Fritz Angle Algorithm for Cannulating the Right Adrenal Vein
(2) Ensuring Accurate Adrenal Vein Location on Angiograms
(3) Ensuring Safe Contrast Injections in the Right Adrenal Vein
The Fritz Angle Algorithm for Cannulating the Right Adrenal Vein
Cannulating the right adrenal vein during adrenal vein sampling can be difficult. However, there are a few tips that can help alleviate this challenge. The C2 catheter can be modified for optimal positioning within the adrenal vein. Dr. Angle uses a dermatologic biopsy device to punch additional side holes approximately 2 mm from the tip of the catheter. Additionally, it is important to conduct CT scans to help identify the location of the adrenal vein, which is usually one vertebral body above the right renal vein. Maintaining an anterior-posterior view on the C-arm and methodically adjusting the catheter position while repeatedly infusing contrast, helps to accurately locate and access the right adrenal vein. Proper use of cone-beam settings allows the operator to safely determine the catheter position relative to the adrenal vein.
[Dr. Aparna Baheti]
…Walk me through the Fritz Angle algorithm for how you get into that right adrenal vein.
[Dr. Fritz Angle]
Okay, well, first off, I do always do the left side first because it's easier and the catheter is really stable, but we could talk about that in a minute because you're right. The hard one is, what do you do with the right? I think most experienced operators agree that the C2 is the go-to catheter for this. That works probably 80% of the time.
[Dr. Aparna Baheti]
Just to interrupt you for a second, you're talking about a C2 that has the extra side holes in it, correct?
[Dr. Fritz Angle]
Yeah. Real important point, and we'll put a side hole, and I put that really close to the tip, like 2 mm from the tip because I want that side hole to be literally in that adrenal vein if I can. We'll punch a little side hole used to be the cook side hole punch set, which we used forever, but it is no longer available.
[Dr. Aparna Baheti]
Did it accidentally get tossed and can't reorder it?
[Dr. Fritz Angle]
That's right. You can't reorder it. Re-sterilized the same set of punches, probably for a decade, and finally, they got bent or dull or lost or whatever. But fortunately, you can use a biopsy that's used actually for skin so you can use a dermatologic biopsy, and this device, you get the 0.3-millimeter ones, really small, and you can punch a hole that's just the right size. It does almost always go through both sides, by the way, but don't worry about it. That's fine. We just double-wall it. I usually do it on the bottom of a plastic bowl so I don't ruin my sterile field. If it goes through both sides of the catheter and down into the bowl, that's fine. Just don't use the bowl because it'll leak all over.
[Dr. Aparna Baheti]
You got your catheter, your C2 made, your modified C2, and now how can you get into that right adrenal vein?
[Dr. Fritz Angle]
I've got a good idea from the CAT scan where it is, but the thing Dr. Matsumota taught me is that it's almost always exactly one vertebral body above the right renal vein. First thing I do is drop that catheter in the right renal vein, which is easy to find, and save a levity loop of that. So I've got a mental image of where that is. I'm focusing my attention just about exactly a vertebral body above, straight posterior.
[Dr. Aparna Baheti]
Okay, so you're straight AP with your II, or do you do an obliquity?
[Dr. Fritz Angle]
No, I almost never, that's a good point. I think most of the time, an AP view keeps you oriented. Once you're in it, lateral views or comb beams we can talk about that but just in terms of that catheter work. In fact, I always liken it to sort of mowing the lawn because what I do is I put the thing just about a vertebral body above, or pull it down slowly, puffing contrast, didn't see anything then I'll go back up, turning it a little bit, just going next to the previous path, and do again, and just keep going up and down, up and down, turning it just a few degrees.
So I get the whole back wall of that IVC searched looking for it. It's not something where you see it plop in, and you're like, "Oh, I'm clearly in something let's puff now." It's kind of a deal where you've got to keep puffing contrast. So doing this procedure as someone who has severe renal deficiency can be problematic.
[Dr. Aparna Baheti]
Sure sure. Okay, yeah, that's the part that takes forever is just trying to figure out exactly where that right is.
[Dr. Fritz Angle]
Yes. I'm doing half of vertebral body above and below where I think it is. It keeps the zone I'm mowing very small. Small yard. I got a small yard and if I don't find it, I start looking a little bit left of center and a little bit right of center. Usually, from the CAT scan, I've got an idea if the adrenal vein looks like it's a little bit off to the right or straight in the posterior.
[Dr. Aparna Baheti]
What do you do if you just keep selecting other veins, like hepatic veins, accessory hepatic veins, and you feel like you were talking about where the confluence of that vein is very close to one of the other veins?
[Dr. Fritz Angle]
Yeah, your biggest problem is you keep finding things that you're really confident are hepatic veins, and you can't find the thing that you're looking for and that's a usual frustration. My first piece of advice there is to switch to a different catheter pretty quickly what's that mean? Two minutes of fluoro, probably time to think about a different catheter. A lot of different operators use different catheters, but I find a Mickelson or maybe a Left Gastric or even a Simmons 1 is a good choice and they have varying degrees of pointing down this that you need to change. You try one of those and see and, of course, when you first start, you see how big a cava it is.
Sometimes you can just tell that the C2 is just rattling in that cava it's not even touching the back wall. Then I'll go straight to one of those reverse curved catheters. Sometimes the vein has got a real caudal tilt on it the C2 just slips over it every time and you never see it.
[Dr. Aparna Baheti]
I see. Yeah that's some very good technical points of how long you should flex around with one before switching.
[Dr. Fritz Angle]
Most of the time it's not like, "Oh, I've looked everywhere. It's got to be in a common trunk with this hepatic vein," that's not usually the case. Usually, it's just that you get into some trunk that you can't quite tell if it's just a hepatic vein or it's a hepatic vein and adrenal vein and that's where you got to, I think, break out the cone beam CT. That's so helpful. See, you get into something it's like, "Well, I think it's right where the adrenal should be but, boy, it sure looks like I'm filling in a hepatic vein." Maybe you don't see the collateral's running off into the right or middle hepatic vein. That's a good place to do a cone beam, then you really know you're in the right place or not.
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Ensuring Accurate Adrenal Vein Location on Angiograms
Navigating adrenal vein sampling demands precision, and the aspect of confirming correct adrenal vein placement in angiograms stands out as a significant challenge. There are a few distinctive visual cues to determine the accurate positioning within the adrenal vein. A triangular or upside-down Y shape, characterized by a fine branching pattern, indicates the right place. However, a rounder appearance resembling a guitar pick, with branches extending beyond the blush to the hepatic vein, signals incorrect placement. Despite these visual aids, certainty is not always achievable, highlighting the value of cortisol level testing. While modern laboratory constraints may cause delays in cortisol testing, its utility in confirming correct vein placement remains undeniable, representing a crucial tool when available.
[Dr. Aparna Baheti]
…How do you know on an angiogram that you're in the right adrenal vein?
[Dr. Fritz Angle]
You love to see that sort of upside down Y shape, that sort of triangular shape. It's usually very fine branching pattern. If you're in a hepatic branch, it can sometimes be a little bit rounder, looks more like a guitar pick, if that's what you're seeing, you're probably not in the right place. Obviously, if you see some branches that go beyond that blush to the hepatic vein you're in the wrong place, and if you see some go in the retroperitoneum, it might be okay but you can get into an intercostal vein. It's usually not it but sometimes there's a commonality with hepatic veins or with the intercostal or even capsular branches of the kidney.
Those are secondary signs I look for to help me decide if I'm in or not in the right place. So it's an art. I'll tell you. I've searched for years to find the right terms to describe what the blush looks like. I say this is the hardest part of this procedure is knowing from an interventional standpoint is am I in the right place or not. Years ago, in our lab, you could send off a stat cortisol, which was great because you get this blush of like, "I don't know," and you do a cone beam, like, "I think it's okay."
We can send a state cortisol level, because if you're in the right place, cortisol levels are going to be high, and if you're not in the right place, they're not going to be high. Now our lab has gone to some automated machine that takes 45 minutes to get a cortisol level run, which means it takes an hour to get it back, and it's just not practical anymore. If you still have a place that can do stat cortisol, that's a great trick.
Ensuring Safe Contrast Injections in the Right Adrenal Vein
Adrenal vein sampling is a delicate procedure, and gentle contrast injections should be done to avoid damaging the adrenal gland. Additionally, a strong contrast injection could kick the catheter out of the adrenal vein, requiring the operator to cannulate it again. An over-injection could potentially box patients out of undergoing the necessary operation, leading to post-op complications like adrenal insufficiency. The goal is to avoid seeing a blush during injections, aiming instead for a ferny pattern. An alternative to contrast injection is using a 0.014 wire through the catheter, eliminating the need for contrast and thereby mitigating radiation exposure. This tactic not only helps to ascertain accurate positioning but also aids in efficient blood extraction from the adrenal vein, addressing many of the procedure's challenges.
[Dr. Aparna Baheti]
…One of the things you worry about when injecting the adrenal gland is injecting too forcefully or too much. What are your settings for your cone beam that you use to prevent that? Because when you're hand injecting, you can kind of control it but once you have your cone beam in place, what do you do?
[Dr. Fritz Angle]
Yes, super important point. You got to be really gentle, and going all the way back to the beginning of this talk, I always tell patients, complication I worry most about is if you over-inject the healthy adrenal gland, you box them out of getting the operation they need because if you blast, the good gland, give it a venous infarct. How would they know that? Well, unfortunately, you may not find it until post-op when they get adrenal insufficiency. It's just something you want to be really careful about. I don't ever want to inject hard enough that I'm seeing blush. I want to see that sort of ferny pattern, but I don't want to see a blush. So gentle injections.
Now, when it comes to the cone beam, fortunately, almost never have to stand in there and use contrast because I figured out and I'm sorry I can't give credit, but I heard this talk I saw years ago. You put an 0.014 wire through that catheter and push it into the branch you're interested in to be forced on the back then you do just a dry scan. It's really like the 0.014 wire. Is it pointing at the gland or is it pointing at the liver and you got your answer?
[Dr. Aparna Baheti]
Wow, that's amazing.
[Dr. Fritz Angle]
Yeah, because we've got one of these little electronics, safe badges now. We stand in there, you just can't believe how fast you eat the dose up standing in there. No matter how you do it, standing in there for cone beams is a bad idea so don't do it.
[Dr. Aparna Baheti]
Life tips.
[Dr. Fritz Angle]
We used to do this a little years ago, but not anymore. So if I got any questions, I just put a 0.014 wire in there. Actually, that trick often helps with the sampling because the second hardest thing about this procedure, besides selecting the right adrenal vein, is getting the blood out of the adrenal vein.
Podcast Contributors
Dr. John Fritz Angle
Dr. John Fritz Angle is the division director of vascular and interventional radiologist and a professor with University of Virginia in Charlottesville.
Dr. Aparna Baheti
Dr. Aparna Baheti is a practicing Interventional Radiologist in Tacoma, Washington.
Cite This Podcast
BackTable, LLC (Producer). (2023, June 2). Ep. 328 – Adrenal Vein Sampling [Audio podcast]. Retrieved from https://www.backtable.com
Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.