Minimizing Nontarget Embolization (and Maximizing Efficacy) in Prostatic Arteries
Updated: Mar 11, 2019
The consequences of nontarget embolization can deter interventional radiologists and patients from following through with a prostatic artery embolization (PAE) procedure. PAE experts Dr. Sandeep Bagla and Dr. Ari Isaacson discuss their PAE technique, why it's effective, and how it helps them minimize nontarget embolization.
The BackTable Brief
The ‘perfected’ prostatic artery embolization (PAE) technique is to start with smaller beads (~100 micron) and upsizing as you get closer to stasis.
When the ‘perfected’ technique is not possible (e.g. due to tortuous anatomy), Dr. Bagla places his catheter at the prostatic capsule (or closer) and embolizes to complete stasis.
Smaller beads have the advantage of providing deeper penetration into the prostate and greater perfusion throughout the prostatic arteries, but carry higher risk of nontarget embolization.
Critical shunts often escape detection during pretreatment imaging. Extra steps should be taken to double check for extraprostatic anastomoses and collaterals after partial embolization.
Disclaimer: The opinions expressed by the participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
The ‘Perfected’ Prostatic Artery Embolization Technique
Okay. Now Sonny, let's get into the embolic agents that you use for a second. Tell us what you use, what's your endpoint, and how LUMI beads might be able to change how you embolize the gland?
Sure. Over the years, I think early on we were using beads and back in 2011, we were using beads that started out in size around 250 micron. We were then finishing with embolic that was in the 400 micron size. When we were using Embozene, which at the time was made by Celenova ... We still use Embozene, however, we have gone smaller in size. About three or four years ago, we switched to smaller size, starting almost invariably at the 100 micron size. Then, upsizing as we reached stasis.
The reason why we did that, is because early on we saw a relatively disproportionate number of early reoccurences, and whether it was just our feeling or not, we just felt as if we didn't get enough tissue ischemia, and deep penetration with those beads. There's no doubt that smaller beads cause more ischemia, but they of course come at a risk of potential non-target embolization. As long as we were comfortable with the angiogram, and thought that there was no risk for non-target embolization, in terms of flow dynamic, and appearance on the angiogram, then we invariably, even in very large glands, start with smaller size beads, and then upsize accordingly so that we can take out what we consider primary, secondary, and tertiary branches within the process.
The ‘Unperfected’ Embolization Technique
Now, assuming you're not using the perfected technique, what is your end point typically?
One quick thing unperfected, I would say from time to time we do use it, I think that overall though, however, if you're using a smaller bead size, it really achieves the same effect that you would from the perfected technique because of course you're going to get more distal penetration with the smaller bead than you would larger.
Invariably, the perfected technique is not necessarily feasible on a good number of patients, who are 30% to 40% of patients, just because the tortuosity of the vessel, and being able to advance your catheter. We place our catheter at the prostatic capsule, if not closer, and we embolize to complete stasis.
There's no doubt, when you're doing a prostatic embolization, you're really aiming to take out the whole organ, more than you are in HCC, for example, [where you’re] taking out a small liver tumor within a very large liver.
Taking Extra Steps to Minimize Nontarget Embolization
In terms of shunts, and unexpected perfusion of the rectum or the bladder, what findings there are okay to go ahead and treat?
...Myself and Ari, and I'm sure I could speak for him comfortably with this, we would of course feel more uncomfortable having non-target embolization to penile arteries, versus rectal arteries, just because one would be invariably noticeable to the patient, versus the other.
That being said, there are so many variations of potential non-target embolization that have to be addressed during the procedure. Something that we see every week, I will tell you, even like Ari said, "Excited about seeing a large gland.". Just on Friday, doing a large gland embolization, you walk in, you're all confident, and you end up with a potential non-target that you have to deal with. That happens with even the simplest of cases...
I think the thing that you need to keep in mind, especially people who are new to PAE, or considering starting, is that there are these extraprostatic anastomoses in nearly every case, and if you don't see it initially, if you do another angiogram after partial embolization of the prostate, you'd probably see it.
You do have to be cognizant of that. I think if you don't look for the shunts, and you just embolize to stasis, and you're using smaller particles, you're going to get yourself in trouble. It's important to do good angiography, and identify the shunts ahead of time, and come up with a good management plan. Again, Sonny and I will talk about the different options for managing those types of things at Stream.
In general, like Sonny said, penile shunts, penile collaterals, are the scariest, and the last thing you want to do is give a patient a skin lesion on their penis, or cause them to have less erectile function than they had before. That's definitely something that can deter a bunch of men from wanting to have a PAE.
If you have non-target to the rectum, the rectum, as you know, is a very vascular organ, and you may get some short term hematochezia but most of the time that resolves within the first week or two, and usually there's no other sequelae of that, so at all costs avoid embolizing the penis. I wouldn't say don't embolize the rectum unless you have to, or if you do, do it with larger particles.
Dr. Sandeep Bagla is a practicing interventional radiologist with the Vascular Institute of Virginia.
Dr. Ari Isaacson is a practicing interventional radiologist with the UNC Department of Radiology in North Carolina.
Dr. Michael Barraza is a practicing interventional radiologist with Radiology Alliance in Nashville.
Cite this podcast:
BackTable, LLC (Producer). (2017, November 27). Ep 17 – Prostate Artery Embolizations [Audio podcast]. Retrieved from https://www.backtable.com/podcasts
The Materials available on the BackTable Blog 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 or its sponsors.