Skip to main content

Transradial Approach for Interventional Oncology: An Interview With Darren Klass, MD

Transradial Approach for Interventional Oncology: An Interview With Darren Klass, MD

You must login or register to download this PDF.
Author Information:

Interview by Jennifer Ford


Darren Klass, MD, PhD, MRCS, FRCR, FRCPC, is an interventional radiologist at Vancouver Coastal Health, in Vancouver, British Columbia, Canada. He is head of the MRI division and specializes in interventional oncology, aortic intervention, peripheral vascular disease, venous disease, venous access and MR angiography. He also practices with Vancouver Imaging, a physician-led private practice also located in Vancouver. Dr. Klass also leads courses for the Merit Medical ThinkRadial radial access training program. Interventional Oncology 360 spoke with Dr. Klass about the transradial approach for interventional oncology procedures.

IO360: What is your personal experience with the transradial approach for interventional oncology? 

Klass: We started using the transradial approach around April 2014. The first case I performed was for a young man who had undergone 3 unsuccessful femoral approaches to access the arterial supply to his liver. We needed an alternative access point because of challenging anatomy, and the options were either a percutaneous brachial approach or otherwise a cut down of the brachial artery. The vascular surgeons here in Vancouver prefer brachial artery cut-down over a percutaneous brachial approach because percutaneous brachial artery access has such a high complication rate. We opted for a transradial approach and it was a very successful procedure. Since then, my interventional radiology colleagues at Vancouver General Hospital and I have adopted the transradial approach. Now, I would say my personal practice is about 90% radial for interventional oncology, and our practice does about 80% of its interventional oncology procedures with the transradial approach. That includes chemoembolization, all of the procedures associated with radioembolization, and bland embolization. 

IO360: What level of adoption of the transradial approach do you see in North America in general?

Klass: I think it varies by institution based on whether radiologists decide to invest in using the transradial approach. It has a lot to do with the mindset of radiologists. You have to look at it as a paradigm shift in terms of patient-centric care. When we do a radial procedure on a patient, we benefit the patient not only in terms of safety, but also in patient satisfaction. The RIVAL study randomized over 7,000 patients to radial or femoral access for coronary procedures, and showed that patient satisfaction is significantly higher with a radial procedure as opposed to a femoral procedure. The cardiology literature shows that currently about 25% of interventional procedures in the United States are radial, so if within the next 5 years this has increased to 30%, that will be a good achievement. Personally, I think if 50% of radiologists have incorporated radial into their craft within 5 years, that would be a huge milestone for the procedure itself. I think that’s quite optimistic. That’s a hope of mine - that many radiologists will see the benefit. As we gather more data, I think more radiologists will realize that this is not just something new and exciting, but it completely changes how we treat our patients and how the patients experience any procedure that they undergo. 

IO360: Are you seeing interest in the interventional oncology community in adopting the transradial approach?

Klass: What interventional oncologists care about is whether or not the procedure that’s done at 3 in the afternoon requires that patient to stay overnight and therefore requires that patient to have a bed. Oncologists and interventional oncologists are seeing more than anything else that they can now do a procedure on a patient that is almost completely outpatient based regardless of the time of day that you do the procedure. In contrast, for a procedure done with a femoral approach, the procedure would have to start in the morning so that the patient had enough time through the afternoon to recover and be safe to go home. From a radial point of view, because the recovery is so fast, there’s no time of day that precludes the patient from going home. From a patient perspective, that’s huge, especially for patients with very short prognoses who are having procedures done for palliation. One night in the hospital is a significant portion of their lives, so they want to avoid an overnight stay if possible. 

IO360: Is the approach being used more because technology is improving?

Klass: Yes. If you look at how the technology has improved over the last 5 years; sheaths, the access devices, and catheters have all improved dramatically so we can now do a chemoembolization through a 4 Fr or 5 Fr system, which again helps significantly with patient recovery. As companies improve technology in general, I think the procedure will become faster and we’ll have a lot more options in terms of what we can do. 

IO360: What is your personal opinion on the most important benefits of using this approach?

Klass: I think the most important things are patient recovery and safety. Radial is clearly associated with lower rates of complications than femoral access. In addition to that, the ability for patients to ambulate immediately after the procedure is very important, especially in procedures that we do where patients are not unwell immediately after the procedure, such as drug-eluting microsphere chemoembolization, or radioembolization. All these patients feel fine after the procedure. They can sit up right away, they can read a newspaper, have something to eat, send emails. If they have the procedure done with femoral access, they lie down for 2 hours to 6 hours after the procedure to recover. 

IO360: Are there times when you would choose not to use transradial – situations where it doesn’t work very well?

Klass: Yes, there are a number of contraindications to radial access. One is if you don’t have an adequate collateral blood supply to the hand. I do a test at the beginning of the procedure called a Barbeau test, which is the only objective way to test blood supply to the hand. There are 4 different classifications in the Barbeau test, of which Barbeau D is an absolute contraindication. Only about 2% of the population have a Barbeau D waveform, which means that they can’t safely have a radial procedure. Another contraindication would be for a complicated procedure that required a sheath larger than 7 Fr. I prefer to use femoral in that case. Also, previous surgeries in the forearm and dialysis fistula are not absolute contraindications, but in those cases I would think about using the femoral artery instead of the radial artery. Some of my colleagues treat dialysis fistulas via the radial artery, so it’s not a contraindication for everyone.

IO360: What are the tools or devices that could still be optimized to make transradial as safe and easy as possible?

Klass: I think we need longer guiding catheters. The difference between a guiding catheter and a diagnostic catheter is that the inner lumen of a guiding catheter is bigger so you can get more devices through a guiding catheter, but unfortunately all the catheters on the market at the moment are 100 cm long. For about 50% of patients this is fine, but there are the patients who are taller or have longer arms for whom 100 cm is a bit too short. So, if you have a complication where, for example, you have to retrieve a coil because you placed it in the wrong position in an artery in the liver, that becomes quite challenging if you’re using the radial option because the guiding catheters that you need to get the snare into the right position are still a little bit too short. As the technology grows and develops, it will become a lot safer, and for about 80% of cases the technology we have at the moment serves its purpose. We also need longer wires, because even 300 cm can be short for certain procedures.

IO360: Do you have any tips for a vascular clinician or interventional radiologist who wants to start incorporating the transradial approach and maybe needs to get their facility’s administration on board?

Klass: There are a number of things. The first one is to make sure you have both the nurses and technologists on board if you decide to start the practice. That for me is paramount and I teach that in my course as a very important facet of radial access. It’s not just about accessing the radial artery. It’s about making sure that the team you are working with understands what they’re doing and are comfortable with the access site. The second tip is from an administration point of view. Looking at the numbers, if you use the radial artery instead of the femoral artery for access for any interventional oncology procedure, you immediately save at least $200 per case if you use a closure device for the femoral artery. Femoral closure devices are about $200 or so each, whereas a radial closure device – a hemostasis device – is about $20. Immediately you are saving money for your hospital regardless of anything else that you do during the case from a cost savings point of view. On top of that, the fact that you don’t have to admit your patients after the procedure itself is again a huge cost saving measure. And radial access patients don’t require as much nursing care after the procedure. So there is not only cost savings, but also manpower savings and saving on beds. So approaching your administration with those three points provides a lot of evidence and a good basis for getting your administration on board.

IO360: How about managing common complications?

Klass: When you start doing this procedure it’s important to have training not only in the access and how to get access but also how to deal with complications. There are a number of potential complications. Bleeding is one, but it is actually quite easy to control, because we have a number of devices that we use to compress the radial artery at the end of the procedure so that it’s controlled and safe and to make sure the radial artery stays open throughout the hemostasis process, called patent hemostasis. Radial artery spasm is another complication that can occur in any stage of the procedure. Having a good algorithm for treating radial spasm is important. This is difficult to teach in a single lecture, and that’s why we encourage physicians who want to start doing radial access to attend a radial course. We teach how to set up the room, how to train nurses, how to get access, what devices you need, and what to do when you encounter these rare complications and to make sure you can complete the case without putting the patient at risk.

IO360: Are there any published data that you recommend clinicians read?

Klass: Two major cardiology studies, MATRIX Access and RIVAL are large randomized controlled trials with at least 3,500 patients in each arm, in each study comparing radial to femoral access. MATRIX Access (Minimizing Adverse haemorrhagic events by TRansradial access site and systemic Implementation of angioX) randomly assigned more than 8,400 patients at 78 hospitals in 4 European countries to undergo angiography via the arm or the groin. The RIVAL (Radial Vs. Femoral Access for Coronary Intervention) study enrolled 7,021 patients from 158 hospitals in 32 countries: 3,507 patients were randomly assigned to radial access and 3,514 to femoral access. These studies showed significant benefits for patients using radial access mainly for the bleeding complications afterwards. But the RIVAL study also showed that an overwhelming number of patients preferred radial to femoral. Ninety percent of patients who had a radial procedure reported they would choose it again, whereas only 49% of the patients who had femoral access would choose it again. The MORTAL study, a database from British Columbia looking at almost 40,000 cardiology patients, showed that when there is an access-site bleed that requires transfusion, the mortality rate increases significantly. Bear in mind these are cardiology studies with high-risk patients. But much of the data, especially the mortality data, can easily be extrapolated to patients who have had high-risk radiology procedures. Those 3 studies are ones that I would urge clinicians to read; they are well constructed randomized trials. I would also recommend a paper published in 2015 by Posham et al that details the initial 1,500 radial cases specifically for radiology (“Transradial Approach for Noncoronary Interventions: A Single-Center Review of Safety and Feasibility in the First 1,500 Cases.” DOI: That study of 1,500 patients included a number of patients that had chemoembolization, radioembolization, and bland embolization.

IO360: Is there anything else that you would like to add specifically for interventional oncology clinicians? 

Klass: Radiologists often ask me how I deal with the risk of stroke when I do a radial procedure compared to a femoral procedure, and it’s important to address this. Again there’s a number of published studies in cardiology literature looking at stroke risk and there’s about a 0.1% risk of asymptomatic stroke – and I think it’s important to emphasize these are asymptomatic strokes. These are not patients that develop any symptoms; these are incidental findings on CT or MRI after the procedure. It’s a very low risk and actually the risk of symptomatic stroke is vanishingly small. For some reason, radiologists have used stroke risk as a deterrent for using the radial artery for access, but actually the overwhelming evidence is not in favor of femoral vs radial when it comes to stroke risk. Again the risk of developing a stroke if you use the femoral artery in interventional oncology is probably higher because you need to form a number of different catheter shapes in the arch of the aorta, which you don’t have to do with the radial approach. Just trying to form a catheter in the arch of the aorta is significantly more traumatic to the wall of the aorta than it is just passing a small very low-profile catheter through the arch of the aorta as you do with radial. This to me is not a reason to avoid incorporating this procedure into an interventional oncology practice. I have yet to find a sensible reason why more interventional radiologists are not using the radial artery.

Editor’s note: Dr. Klass reports consultancy to, payments for education presentations from, and travel reimbursements from Merit Medical. For more information on ThinkRadial, or to register for an upcoming course, visit

Suggested citation: Ford J. Transradial approach for interventional oncology: an interview with Darren Klass, MD. Intervent Oncol 360. 2016;4(3):E55-E60. 

Back to Top