Ask the Expert

Enjoying and Teaching the Ins and Outs of Transradial Access

Cath Lab Digest talks with Sandeep Nathan, MD, MSc, FACC, FSCAI, ThinkRadial Course Director and Associate Professor of Medicine, Medical Director, Cardiac Intensive Care Unit,  Director, Interventional Cardiology Fellowship Program and Co-Director, Cardiac Catheterization Laboratory at the University of Chicago Medicine, Chicago, Illinois.


Cath Lab Digest talks with Sandeep Nathan, MD, MSc, FACC, FSCAI, ThinkRadial Course Director and Associate Professor of Medicine, Medical Director, Cardiac Intensive Care Unit,  Director, Interventional Cardiology Fellowship Program and Co-Director, Cardiac Catheterization Laboratory at the University of Chicago Medicine, Chicago, Illinois.


Can you tell us about the cath lab at the University of Chicago Medical Center?

The University of Chicago is a large, quarternary medical care center in a very urban environment. We see walk-in cardiac illness as well as a great deal of referral business from other institutions. We have a total of 5 cath labs, with 4 full-time interventional cardiologists. I serve in the role of co-director of the cardiac cath lab and medical director of the cardiac intensive care unit (CICU). We have been involved in the radial space since 2008 and since the program’s inception in 2008, our radial volume has continued to grow year after year. 

Can you tell us about how the radial program began?

We had a 100% exclusively femoral lab at the time. In late 2007/early 2008, I became intrigued by the prospect of transradial intervention and read as much about radial access as possible. There wasn’t much available in the medical literature, but what was available was persuasive enough for me to seek out training. I attended a hand-on course with Dr. John Coppola, then at St. Vincent’s Hospital in New York. I began our radial program with the assistance of some nurse and technologist champions shortly thereafter, in 2008, and we have never looked back. Some of my colleagues also were quick to jump on the bandwagon and the program picked up momentum quickly.

It really has been a transformative therapy for our practice. I would submit that transradial is equally impactful irrespective of the type of practice, whether community-based, a tertiary/quarternary care center, or an academic practice. Irrespective of the type of patients you are seeing or the acuity of the patients you are generally seeing, radial has an impact. It certainly has had an impact at the University of Chicago. 

What have you observed since transradial access was implemented at the University of Chicago Medical Center?

It is interesting to note that the routine use of radial approach in our lab has been an engine of growth. Internal, external, and self-referral volume have all been positively impacted by the program. We have also found some unlikely champions of the procedure within and outside the institution for a variety of reasons. Some of our cardiothoracic surgeons request radial approach for pre-op patients, as it leaves femoral access untouched for cardiopulmonary bypass access.  Providers referring patients with liver failure, coagulopathies, or anticoagulated patients request radial for obvious safety reasons. Our center serves a large Jehovah’s Witness population and as their religious beliefs forbid transfusion of most blood fractions, they too have sought out a radial approach when their care calls for invasive catheter-based procedures. The radial approach also has a big fan base with nurses and medical trainees who no longer have to tend to femoral vascular access sheaths, and the discomforts and complications therein.

When you began the program in 2008, was there the same awareness of the benefits of radial access as there is today, 8 years later?

The move towards radial was leveraged on promising data, albeit much softer than what we have available today. It was based on decrease in bleeding risk and decrease in vascular complications. Many of the benefits that we recognize today are now supported by the literature and easily translatable to clinical practice. Those data had not even been generated in the U.S. cardiology community at that time. Some data was present, but there were a lot of unanswered questions back in 2007.

Can you tell us more about the hands-on radial course you attended?

Working with Dr. Coppola was tremendous. He is an unbelievably skilled operator. He was very generous with his time and expertise. A hands-on or at least a very intensive experience, where information is being delivered by someone who lives it day in and day out, and possesses a wealth of experience, makes all the difference in the world as you are trying to get a program started.

How are radial procedures facilitated at your lab?

In the spirit of disclosure, I should say that not everyone is fully on board with radial as a default approach, but it has become a standard enough approach that it is the default setting when most patients are prepped, certainly for myself and some of my partners, who are very much invested in the radial space. It is our default prep. We have a total of 4 cath labs and one hybrid operating room. The things we have implemented to improve the efficiency and ease of performing radial procedures include a standard setup for left radial and right radial, dedicated drapes, and an understanding among all nurses (and frequent refreshers) as to how we would like these cases set up in terms of ergonomics and equipment. When you are performing left radial procedures, ergonomics becomes an absolutely critical issue. We experience some variations depending on the lab in which we are working; for example, the biplane suite has a higher table to accommodate the lateral camera. In this lab, a left radial approach is a little more challenging, but there are some fairly straightforward workarounds to ensure we are able to accommodate radial procedures in all of our spaces.

What is your percentage of radial cases?

The lab as a whole is over 50% radial at this point. I do radial for my coronary procedures, peripheral diagnostics, and some of my peripheral interventions. Drilling down on coronaries as the bulk of my practice, I would say I am at 75-80% radial.

How do your fellows react to the radial approach?

The fellows are uniformly thrilled with radial, because no sheath ever leaves the cath lab. Having to compress the sheath becomes a non-issue with radial. I think they also quickly recognize the benefits of a radial approach. Since they are on the front line, they get those calls saying, The patient is hypotensive. Do you want to come take a look at the groin site? Even before they are facile with the data, they understand on a visceral level that there are some tangible and importantly, reproducible, benefits to radial. Fellows are uniformly enthusiastic about radial and if they had the ability, I think they would convert every single case to a radial case. In the spirit of balance, we all instruct them to become very comfortable and very skilled at safe femoral access, because femoral access isn’t going away, especially large-bore femoral access. You have to be very skilled with obtaining and managing femoral access sites during and after the procedure. We try to balance that at the beginning of the year, but as the academic year wears on, the lab typically becomes a higher and higher percentage of radial once the first-year fellows have become facile with femoral access.

Do you prep the groin in radial cases?

Not uniformly. If there are radial patients who are therapeutically anti-coagulated with warfarin or a novel oral anticoagulant, conversion to the leg in a non-emergent situation engenders an unacceptable level of bleeding risk, and we are much more apt to go to the other radial before we even consider the leg. In rare instances, the patient will usually need to come back and be taken off their anticoagulation with bridging therapy as appropriate. Thankfully, that kind of conversion is sufficiently uncommon enough that we don’t prep the leg in those circumstances. For emergency cases, the leg is prepped along with the radial artery, as it is for standard cases where the leg would be a viable option, but we generally don’t open up the leg. We don’t even open up the fenestration on the drape until we have really exhausted our possibilities from the arm. 

You talked about the ergonomics of left radial access. Can you share what you have learned?

I would say that a solid one-third of our cases are left radial cases, so first and foremost, we as operators and trainees get ample exposure to working with the left radial. A transfemoral background will offer some familiarity with catheter manipulation from a left radial approach versus a right radial approach. The key is not to have to lean excessively over the patient in order to get to the arm. What does that mean in practical terms in our lab? The arm has to be prepped at the side of the patient and then elevated, ideally above the level of the thigh, so that you can easily access it without having to lean over the patient. Some operators have endorsed the movement of the arm once access is gained, all the way over the thigh or perhaps over the midsection of the patient’s body. If you have special equipment to support it and you are comfortable, that is fine. We generally prep the arm at the side, obtain access, and then elevate the arm and pronate it slightly so that standing at the right side of the table, it can be easily accessed. 

Can you describe your workhorse equipment related to radial procedures?

Among the four interventional operators in our lab, everybody likes slightly different equipment. What we all agree on is that smaller is better from a radial approach. If you can do your case with 4 and 5 French access, that is perhaps better than irritating the vessel with 6 French access, when 6 French catheters aren’t necessary for diagnostics, as an example. I am a much bigger fan of universal catheter curves than some of my colleagues. Judkins is fine as well, with some minor tweaks to the sizing of a Judkins left catheter if you are going from the right radial approach versus the left radial approach. As far as guide catheters go, many of the femoral workhorse guides that we use and stock anyway, work just fine, irrespective of right versus left radial. Extra back-up type curves that abut and gain backup force from the contralateral wall of the aorta all work very well for radial intervention. Universal guides are fine as well, as long as you are comfortable manipulating them. Universal guide catheters do require a little more manipulation and experience as compared to Judkins and more standard guide catheter shapes. Despite individual equipment preferences, our operators all encourage and agree with the use of smaller catheters, minimizing the number of passes through the wrist if possible, and using equipment you are comfortable with, that doesn’t require an excessive amount of manipulation. Use does vary between left radial versus right radial. For a left radial approach, we almost all use standard Judkins type curves with very little deviation. Obviously, when you are trying to get through graft anatomy, you have to customize it to the various anatomic issues you are encountering. 

What about using ultrasound to gain access?

I don’t think we use ultrasound enough. I say that because your best opportunity to get into a radial artery is probably your first stick, and after the vessel has been irritated a few times, you have spasm that sort of haunts you for the rest of the case. The general rule of thumb in our lab is that if it is a bounding radial pulse, and there are no issues with defining the boundaries of the pulse and the best place to gain access, then sticking without ultrasound is fine. However, if there is any other mitigating factor, perhaps low blood pressure, a pulse that is particularly weak, or anatomic issues such that the patient can’t extend their wrist as much as you’d like in order to bring the pulse superficially, we have a relatively low threshold for the use of ultrasound. Personally, if I can’t gain radial access on the first or second stick, my next move is to use the ultrasound. We have the ultrasound ready to go for our cases; it is not something that has to be brought in from elsewhere. It is an important key to getting through the case quickly and effectively.

What are some of the challenges you see for beginners?

Some of the issues for beginners are case selection, technical failure, and the learning curve. Everybody goes through their own learning curve. When you are introducing a new technology into the lab, and it is a new technology that nobody has familiarity with (many of the structural technologies, for example), the expectation is that there will be an uptick in the amount of time you have to devote to it. It becomes challenging for starting radial operators, because everyone in the lab, including themselves, is likely very facile with femoral approach. Initially, case selection to gain good experience and build up speed and confidence is very important. Ergonomics can make or break a case. If your left arm is drifting outward for the entire case, that is going to make for a very tiring exercise. Gaining a body of experience relatively quickly with cases that you can get through without a whole lot of technical challenges goes a long way toward building confidence, building speed, and building skill sets that you can apply to more complex cases. Keep ratcheting up the level of difficulty. Another issue frequently mentioned in the context of starting a radial program is radiation exposure. Radiation exposure is a big deal, irrespective of whether you are talking about coronary work or non-coronary work, or radial versus femoral. Radiation exposure matters, both for the operator as well as the patient. Here again, building up familiarity with the equipment, minimizing time on the pedal, and standing as far away from the access site as possible are all important considerations for the radial operator. Once you get through your learning curve of diagnostic cases and straightforward percutaneous coronary interventions (PCIs), the next big jump for the radial operator comes when they attempt complex intervention in stable patients or any intervention in unstable patients vis-à-vis primary PCI for ST-elevation myocardial infarction (STEMI), which we recognize as one of the bright spots of radial intervention. It is a challenging jump and frankly, many radial operators never make that jump. I think it is important to keep growing your skill set so that you can get to the point where you are able to offer this procedure to the sickest population, which is also the population that might benefit the most from radial access. 

As an experienced radial operator, what challenges do you face?

There are some issues. I do think the equipment continues to get better and better. We are at a vastly different point than we were in 2008, or even earlier. I remember going to learn about radial in 2002 at TCT. There was absolutely no discussion about dedicated, thoughtfully designed equipment, or about troubleshooting and getting past challenges. Education and information have certainly improved. One issue I struggle with is repeat radial access in patients. Occasionally the radial artery is thrombosed or at the very least, the pulse doesn’t seem to be quite as good as when we intervened on the patient last year. Radial reuse is definitely a challenge. The usual anatomic challenges of radial-ulnar tortuousity and loops, and subclavian tortuosity, are still present, although as a seasoned radial operator, you find out what works for you and how you can get through. There are still unmet items on the radial equipment wish list in terms of catheter length and effective working length of therapeutic devices, especially as it relates to peripheral intervention from a radial approach. Those are the issues I struggle with on a personal level. On a programmatic level, getting everyone comfortable with radial STEMI is a big challenge, and not just the operators. It can be tough if you have float pool nurses or technologists without as much exposure to radial cases as your usual nurse or tech crew. Getting everybody up to speed with radial STEMI quickly from a programmatic standpoint can be an ongoing challenge.

What do you see as the future of radial access?

Asian operators have pioneered the use of low-profile devices. In the Western world, particularly in America, we still fall back on 6 French intervention as our default. Partly it is sort of a crutch we have in our mind, that things will be easier if we go with 6 French, but the Japanese, and many others overseas, have pioneered the use of 4 and 5 French access. The availability in the U.S. of dedicated equipment for 4 and 5 French access from a radial approach, particularly 4 and 5 French-compatible guide catheters, will be very exciting to see. Technique is being continuously refined in terms of traversing some of the anatomic challenges. I always learn so many tips and tricks every time I go to a meeting and see what is being presented, or even just in informal dialogue with other seasoned radial operators. You get a sense of what works and what doesn’t work, and discover new ways to address a common problem. A dedicated approach to preserving radial patency as opposed to “Well, we’ve done what we can, hopefully it stays open”, is important, because radial reuse for years to come is what we should be working towards. Anything we can do, whether technological advancements or iterations of the technique employed to preserve radial patency, is a very worthwhile expenditure of effort and investigation. I believe we will be adapting radial for very complex procedures that require larger-bore access. Radial access is the subject of constant technologic innovation and new equipment is being developed that will facilitate our ability to handle nearly everything from a radial approach — that is perhaps where we are going. Femoral will never go away and it is an important mode of access, but if we can convert the vast majority of cases to a radial approach, safely, effectively, and without compromising time, success, and radiation dosing, that is the overarching goal.

What do you recommend for new and potential radial operators?

Some form of dedicated training and familiarity with best practices, equipment manipulation, and traversing challenges, is important. There are a number of courses being put on nationally. If you are dedicated and intent on building a radial program, it is important to go in armed with a solid base of theoretical and technical knowledge. Over the past several years, I have had the good fortune of being involved in a number of training initiatives. Presently I have the great privilege of leading a course called “ThinkRadial”, which is sponsored by Merit Medical in Salt Lake City, Utah. It is a comprehensive immersion course spanning two days. There are a number of other courses as well. Wherever operators go, they should aim to undergo some structured training in the radial approach.

More information on the ThinkRadial course with Dr. Sandeep Nathan is available at:

ThinkRadial course

Salt Lake City, Utah

2016 course dates: 
April 22-23
June 17-18
October 21-22

Disclosure: Dr. Nathan reports serving as a consultant and/or proctor for Medtronic, Inc., Terumo Interventional Systems, and Merit Medical.

Dr. Sandeep Nathan can be contacted via email at or via phone at the University of Chicago Medicine at (773) 702-2697.