Updated: Oct 21, 2020
Transradial access (TRA) has been used by interventional cardiologists since the 1980s, yet has been underutilized by the interventional radiology community until recently. Published in 2003, a paper by Shiozawa and colleagues described the use of TRA for chemoembolization of hepatocellular carcinoma. This application of TRA inspired Dr. Fischman and his partners to apply the TRA technique to their interventional oncology work in 2012. Refinement of TRA applications over time led to an increase in use, as its potential was realized. In episode 30 of the BackTable podcast, radial access expert Dr. Aaron Fischman discusses how to integrate TRA into your practice, what constitutes a complete circulatory examination, and when to reconsider TRA and opt for alternative access sites.
The BackTable Brief
Transradial access may be easier to learn during procedures such as chemoembolization, Y90, and fibroid embolization, says Dr. Aaron Fischman; ultimately it is important to learn transradial techniques on previously mastered procedures.
A comprehensive circulatory evaluation should be performed on all radial access patients; this includes checking pulses, performing a Barbeau test, and ultrasounding the radial and ulnar arteries.
In addition to understanding the circulatory exam, understanding your patient’s vessel characteristics allows you to properly inform the patient about risks of TRA regarding their specific anatomy.
The incidence of both Barbeau type D and radial loops are low, and the circulatory examination may reveal these anatomical complexities; consider alternative access options in cases of complex patient anatomy.
Photo credit: Dr. Sandeep Bagla
Disclaimer: The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
Incorporating Transradial Access Into Your Practice
Integration of transradial access into your practice may be difficult when starting out or when performing a newer procedure. Initial attempts at transradial cannulation should be during procedures that you are comfortable with performing; Dr. Fischman suggests starting with chemoembolization, Y90, or fibroid embolization if these procedures are performed frequently within your practice. [Chris Beck] … I'll tell you that in my practice I'm three years out, and when I first joined my group, there were some more senior IR guys in the group, who I'm their junior by like 10 years. First getting into the practice, being a junior guy, I don't know … I felt like the spotlight was on me to conform to their practice rather than go and turn everything upside down because I was definitely doing some things already very different from my partners. I shied away from radial access at first, but now I'm kind of starting to revisit it. Getting your take on it and maybe some of the roadblocks and tips and tricks to troubleshoot those roadblocks would be helpful. I think like just for those who are either not as familiar with radial access, we'll just start with some of the basics, radial access 101. I guess it always starts with the patient evaluation. Will you take us through what that looks like?
[Aaron Fischman] Yeah, absolutely. Before we go into that, I'll just say that you're absolutely right. It's very difficult, I think, when you're doing a newer type of procedure. I'll just give you an example, prostate embolization. If you're starting that practice, and then you're adding in something else new like radial access on top of that, it can be very challenging. One of the reasons that we were successful in adopting the transradial approach, as I mentioned before, is that we were already doing quite a bit of chemoembolization and that was the procedure that we chose to start with. We had such wealth of experience with that procedure from a femoral approach that it was the right procedure to try that on. I always tell people that if you're doing a lot of something like interventional oncology, chemoembolization or Y90, or even fibroid embolization where you have a pretty busy practice, those are probably the procedures to start with.
[Chris Beck] Yeah, maybe not. Maybe not off with your first prostate artery embolization?
[Aaron Fischman] Yeah. Look, I obviously use radial access for that as well. Again, if you're not familiar with the radial approach, it may not be the best thing to start both at the same time. That being said, it really has a lot of advantages for that procedure in particular. Again, it's a complicated procedure in and of itself. To add something that you're not familiar with on top of that can be very challenging. I would caution people that are just starting out to start with things that they're very familiar with.
Understanding the Comprehensive Circulatory Examination
The decision to perform transradial access hinges upon the preoperative patient evaluation. The Barbeau test is a good screening tool to identify collateral circulation within the hand. Furthermore, Dr. Fischman always ultrasounds the ulnar and radial arteries to understand vessel characteristics. Although small vessels are suboptimal for radial access, anticipating risks of TRA allows you to properly inform the patient of the risks associated with the procedure.
[Aaron Fischman] There are certain things that are very specific to radial access. I always talk about the Barbeau exam, which in general is a good screening test. There are obviously a lot of things that I need to do to the radial artery before I access it. I always ultrasound the radial and the ulnar. It's important to look at the size of the vessel before you access it. It's really important to assess the circulation of the hand using the Barbeau exam. I don't know if we need to go into too much detail, but there are cardiologists now that think that that may not be necessary. For me, it's important to understand the circulation in the hand. It doesn't mean that you wouldn't access a vessel because you think the vessel's small if you know that you can do it, but you do need to understand the risks and you discuss those with the patient. If somebody has a very small radial artery and a large ulnar artery, the chance that you'll access the vessel might be less, but the risks to the hand are basically zero. If somebody has a very small ulnar or even an occluded ulnar, accessing the radial artery may not be the best idea. So, it's really important to understand the circulation.
When would you reconsider transradial access in a patient?
Radial access can be complicated by anatomical irregularities such as radial loops. Reviewing the patient’s medical history is important, however, the comprehensive circulatory examination ultimately dictates whether transradial access is appropriate for the patient. Although cannulation of radial loops is possible, alternative access approaches should be considered in patients with complex anatomy.
[Chris Beck] Let me ask you this and you kind of touched on it. As far as ultrasounding both the ulnar artery and radial artery, are you looking for a size in general? I've heard some people in talks, and I don't do this routinely, but do you go all the way up the forearm checking for any radial loops? I'm assuming you're doing this on the table or maybe in clinic. Do you check for any loops up to the elbow?
[Aaron Fischman] Well, we do a Barbeau exam, and I look at the pulses, and I check that in clinic when I see patients. Typically if I have my pulse oximeter in clinic with me I’ll document that in the medical record. If I’m in the room, my fellow or myself will check it again just to document it. And, yeah, we'll ultrasound as far up as we think we need to go. But to be honest, the incidence of radial loops is so low that I wouldn't say that’s something that comes up as much as people talk about. It's really important to understand the circulation and the Barbeau exam, but the radial loop is pretty rare. You may know that somebody has a radial loop from a previous procedure, and if that's the case, you may not want to access the radial artery if you know that. However, there are a lot of techniques to do radial loop cannulation and access, but you just need to be aware that if there are other options, you may not consider that your first choice.
[Chris Beck] Maybe just anecdotally, but as far as Barbeau type D or radial loops go, we talk about them all the time. These are really the exception, right?
[Aaron Fischman] Most people say Barbeau D is around 1%. Radial loop is probably less than that in my experience. If you look at some of the literature, people talk about 1% for that as well, or 1-2%, but you just don't see it that much. Maybe you have a small loop, but you may not have a full loop. But a real radial loop is challenging, but 50%, 60%, 70% of the time you can get through it.
---------- Podcast Participants:
Dr. Aaron Fischman is a practicing interventional radiologist at Mount Sinai Hospital New York.
Dr. Chris Beck is a practicing interventional radiologist with Regional Radiology Group in New Orleans.
Cite this podcast:
BackTable, LLC (Producer). (2018, June 27). Ep 30 – Transradial Access: Basic to Advanced [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.