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PAE Procedure Workup: The Role of Uroflow and Pre-Procedural Imaging
Bryant Schmitz • Updated Jun 9, 2023 • 231 hits
Prostatic artery embolization (PAE) has been adopted by more and more interventional radiologists in recent years. The rapid evolution of the PAE procedure has led to the utilization of various pre-procedural practices. Questionnaires, Uroflow, CT, MRI, and cone beam CT have been used, among other tools, to work up patients with benign prostatic hyperplasia (BPH) and plan treatment. In an effort to better standardize the prostatic artery embolization procedure, Interventional Radiologist Dr. Sam Mouli explains his approach to PAE workup, including his recommendations on the roles of Uroflow and cone beam CT.
This article features transcripts for the BackTable Podcast. We’ve provided the highlight reel here, and you can listen to the full podcast below.
The BackTable Brief
• Uroflow is not necessarily required in the workup for PAE for benign prostatic hyperplasia; patient management can be based on clinical symptoms and validated questionnaires alone. Cross-sectional imaging (e.g., CT, MRI) is not part of standard BPH workup, and such scans might not be covered by insurance, potentially leading to out-of-pocket costs for patients.
• Cone beam CT is a useful tool for identifying the major blood supply and collateral arteries feeding the prostate during PAE. Collaterals can be found in a significant number of patients, and treating these alongside the main arterial supply may lead to improved long-term success rates for PAE.
• Regardless of prostate size, successful treatment can be achieved as long as patients meet the right inclusion criteria. Clinical experience and the right equipment can offset the need for pre-procedure imaging in many cases, according to Dr. Mouli.
Table of Contents
(1) Standardizing PAE Procedure Workup: Uroflow Metrics & Imaging Requirements
(2) Identifying Prostate Artery Collaterals with Cone Beam CT
Standardizing PAE Procedure Workup: Uroflow Metrics & Imaging Requirements
Drs. Barraza and Mouli explore two potential controversies in the realm of PAE for benign prostatic hyperplasia treatment: the necessity of uroflow metrics and the role of pre-procedure imaging. Dr. Mouli suggests that uroflow is no longer essential for the workup given the growing comfort and knowledge about PAE, and clinicians can often manage patients based on clinical symptoms alone. Regarding pre-procedure imaging, it was highlighted that cross-sectional imaging is not considered standard of care in the benign prostatic hyperplasia workup and is not routinely covered by insurance. Instead, treatment decisions should be based on symptoms and the right inclusion criteria, to avoid potential out-of-pocket costs for patients.
[Dr. Michael Barraza]
Totally. It's been a challenge debating for some of them that haven't or that travel from out of state, how much of the workup I need them to do and I haven't decided, I haven't really come to a conclusion on this like, do I insist that they get uroflow or not? I don't know. How important do you think uroflow is in the workup?
[Dr. Sam Mouli]
When we started doing all this in the beginning and this was stuff that Ari and Sandeep had pioneered early on in like the stream courses and such, that was like a big component of it. I think now that we've gotten more comfortable and there's a lot more data about PAE, is it really necessary? A lot of urologists will manage these patients based on clinical symptoms alone, AUA symptom score, and all these validated questionnaires. Maybe they have a uroflow in the office, maybe they don't, but they're not completely dependent on that for their treatment, and so I don't think we should be either, as long as they have the true diagnosis of BPH, this should be sufficient.
[Dr. Michael Barraza]
I'm with you, Sam. All right, well, here's the next controversy then. What about pre-procedure imaging? Do you ever do this without any pre-procedure imaging? I usually get something if I haven't looked at the prostate. I guess you should make the distinction between pre-procedure vascular imaging or any imaging of the prostate. Kind of interested how you feel about both.
[Dr. Sam Mouli]
The big thing here is, and I know things are different elsewhere in the country, it really depends location to location. Imaging is not typically part of BPH workup. It's not considered standard of care. If a patient goes and sees a urologist, he's not getting an MRI, he's not getting a CT scan to tell his prostate is big unless he has some other indication, cancer, hematuria, something like that. It's not part of the typical workup. If they come to see you and you want to get a CT scan or an MRI or whatever, it can be difficult to get that covered by insurance and then your patient is left with an out-of-pocket cost.
Truthfully, all these minimally invasive surgical therapies are all being done, for the most part in the community, without necessarily getting all this high-level cross-sectional imaging that we would require for IR. That being said, lots of groups have shown regardless of prostate size, you can treat these patients as long as they have the right inclusion criteria in terms of symptoms. I would argue that with enough experience and the right equipment, you shouldn't need cross-sectional imaging to be able to take- a patient to angio and treat them, especially since it's not part of their regular workup and you could be leaving the patient with a cost that they'd have to cover themselves.
[Dr. Michael Barraza] I'm with you. I agree. Most of the time it doesn't add much. I hate to be too anecdotal on here. Two of my last patients that had been referred, I got imaging on them, and the first one had the tiniest prostate that I think I've ever had referred. It was so small. It was like I just don't think I'm going to be able to really add much for you. The other got a bladder full of stones. Again that's very rare.
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Identifying Prostate Artery Collaterals with Cone Beam CT
Prostatic artery embolization (PAE) requires navigation of the pelvic and prostatic arteries. Cone beam CT has emerged as a useful tool for mapping the pelvic and prostatic vascular system. Dr. Sam Mouli underscores the cone beam's value in identifying arterial collaterals, which can be spotted in up to 70% of cases in his experience. The significance of addressing these collaterals lies in the improved 5-year success rates of PAE, as treating all blood supply pathways to the prostate can yield recurrence rates under 20%. By using a cone beam CT to identify and manage these collaterals (often via coil embolization before particle embolization), physicians can 'skeletonize' the gland, ensuring more effective PAE treatment. Also, the use of vasodilators like nitroglycerin and verapamil can assist in redirecting the flow for more efficient embolization of these collaterals.
[Dr. Michael Barraza]
To take this a step further, let's talk about cone beam CT. That's technically pre-procedure imaging and you had brought this up, it is something we should talk about and I agree. A lot of people just going straight to angio doing the embolization and that's it. You and I both agree on cone beam CT.
[Dr. Sam Mouli]
I think in the beginning, cone beam was deemed as something to make sure that we are indeed in the prostate, you're not embolizing the bladder, you're not embolizing some other structures, and that it was like a confirmatory tool. What we found from the initial experience on a lot of the reported literature is cone beam's really valuable, not just for that, but also identification of other supply and collaterals, and so early papers have reported collaterals in the realm of 20% to 40% of patients. I think in my own practice I see them in 60% to 70% of patients.
So why is that important? When I take somebody to angio, what I tell them is, I want to get you to a five-year success rate that matches Tiago's work and matches Carnevale's work, which is basically in the recurrence rate is under 20%. In order to do that, you want to treat everything that's going to the prostate at the same time, identify the major blood supply, but any collaterals that might crop up, and then feed the gland after you've done the embolization. To do that, I really rely heavily on cone beam to make sure that there aren't actual prostatic sources that I need to coil off and such. Yes, I see those in 60% to 70% of cases and I'm doing a lot of coil embolization before we do the particle embolization to facilitate that.
[Dr. Michael Barraza]
You're able to see them a lot of time on your cone beam CT. I don't think that gets talked about enough is using cone beam as a tool to identify collaterals that either need to be embolized or something you got to look out for during the treatment.
[Dr. Sam Mouli]
The way I've been using cone beam, and I think a lot of people started doing it this way is rather than using it once you get into the prostate, I do like basically a pelvic cone beam CT to get a lay of the land, the anatomy, and then look at everything that is going towards the gland. My, "search pattern" for this is I look at what's perfusing the penis on both sides first and then making sure that there isn't a distal pudendal branch that's coming back up towards the prostate or feeding the prostate." Once I've cleared that, if there is, then I try to get into that and coil it off, to begin with. Once I've cleared that, then I look at what's going to the gland on both sides.
Is there stuff from the rectum, stuff from the bladder, et cetera, where's the origin? Then trying to treat all of those vessels at the same time. What we found is once you get over 80 to 100 grams, you're usually going to have two arteries on the right, two on the left, some asymmetry that you just got to get into all of these different vessels.
[Dr. Michael Barraza]
Are they usually big enough to identify the ones that you're going to have to treat, or are they hard to distinguish from some of these collaterals, as you said, from a pudendal that you would coil rather than infuse particles through?
[Dr. Sam Mouli]
Yes, so basically what my goal is to get into all the little ones, if they are several, coil all those off, basically skeletonize the gland, so to speak, and then get into the main supply embolize that with particles to stasis.
[Dr. Michael Barraza]
Going after those at the beginning rather than during your treatment, do this prostate, pelvic and prostatic arteries, do they respond the same way they do in the liver where you could do an embolization and then 30 minutes later, you get redistribution of flow into the rest of the gland?
[Dr. Sam Mouli]
Yes, so that's basically what we've seen in our own experience and then in others have reported this that where do early recurrences come from? It's usually these collaterals that you either didn't treat the first time or didn't see or you missed or whatever. Now, I'm just really vigilant about getting into them, coiling them off up front such that once you treat the main one, you're getting feeling that inflow is cut off, so to speak. You're getting filling of the whole gland. You're not having any missing pieces, et cetera. It's like, as I'm doing the case, it's like a jigsaw puzzle, and I'm trying to piece it together side to side and make sure everything is covered and not missing anything.
[Dr. Michael Barraza]
Do you ever see these collaterals that are big enough that you decide you need to particle embolize as well?
[Dr. Sam Mouli]
Yes. I think the key is you see how much tissue it's perfusing, what's its size relative to your microcatheter, and then when you inject, are you getting antegrade flow, or is it mostly refluxing into territory that you don't want to treat from? One way is you can just do that with the catheter. The other things that I found is using vasodilators, nitroglycerin, verapamil, things like that can help you and redirect the flow such that you can embolize with particles from these collaterals if it's appropriate, and then coil them off when you're done.
[Dr. Michael Barraza]
Now, one more question about cone beam. Not using it so much anymore to confirm. Do you ever do them after you get the microcatheter in and do another one to show how much gland you're perfusing?
[Dr. Sam Mouli]
Typically not. I think the pelvic cone beam gives you a really good lay of the land. Just from a time standpoint, if you want to just move and be efficient, you can estimate from angio how much land you're covering once you've picked everything off that you need to. I think early in your experience, in your first 20 cases or so, you really need it. After that, it gets really second nature.
[Dr. Michael Barraza]
Yes. I'm not at a point where I am interested in getting rid of cone beam in really any sense. Certainly not at the beginning. I'm doing them the way you are. Asked our friend Dave Johnson his protocol and stolen that, for me it's invaluable.
Podcast Contributors
Dr. Sam Mouli
Dr. Samdeep Mouli is an Assistant Professor of Vascular and Interventional Radiology at Northwestern University Feinberg School of Medicine.
Dr. Michael Barraza
Dr. Michael Barraza is a practicing interventional radiologist (and all around great guy) with Radiology Associates in Baton Rouge, LA.
Cite This Podcast
BackTable, LLC (Producer). (2023, January 9). Ep. 280 – Current Controversies in Prostatic Artery Embolization [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.
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