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Angioplasty.Org Interview Series: Transradial Approach
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Interview with Mauricio G. Cohen, MD, FACC

Dr. Mauricio G. Cohen is Director of the Cardiac Catheterization Lab at the University of Miami Miller School of Medicine. A native of Argentina, Dr. Cohen joined the University of Miami in September 2008 after five years at the University of North Carolina School of Medicine where he was an assistant professor, as well as Associate Director of the Catheterization Laboratories and Director of the UNC Healthy Heart Latino Initiative, providing health care services and outreach to the growing Latino community in North Carolina (ed. note -- this interview was conducted just prior to Dr. Cohen's move to Miami.)

Previously Dr. Cohen studied interventional cardiology at Duke University Medical Center, having been honored with the Latin American Society of Interventional Cardiology Duke Scholarship in 1997. After completing his training, Cohen returned to Argentina as clinical research director in interventional cardiology at the Hospital Italiano de Buenos Aires, one of the major referral medical centers in South America.

For more about the transradial approach, visit our Radial Access Center.



Mauricio G. Cohen, MD, FACC
Mauricio Cohen, MD, FACC
University of Miami Miller
School of Medicine

Q: When and why did you start using the transradial approach?
Dr. Cohen: I originally trained in Argentina. By the time I was finishing my general cardiology training, the interventional group at my hospital was doing a randomized study allocating patients to radial, brachial and femoral access. That was in the mid-'90s, when very few people were actually doing the radial technique. Some patients were having radial diagnostic catheterizations, and that was working very well. But all interventions were done via transfemoral access, because the interventional equipment would not fit in a 6F catheter.

University of North Carolina School of Medicine
University of North Carolina
School of Medicine

Then I had the fortune to come to the States and train at a great institution such as Duke. But I noticed the epidemic of obesity that was affecting this country. After a few years, when I became faculty here at the University of North Carolina in Chapel Hill (UNC), I noticed that doing the morbidly obese patients always posed a significant risk.

We were getting a number of patients, who had been referred for bariatric surgery. And all the required imaging studies and stress-testing were not optimal because of the large volume of these patients.

So many of these patients were being referred to cath instead, and every time we had to do a femoral approach in them, we were always afraid the patients would bleed and/or would have a complication. And by the time we realized the patient was having a bleeding complication, the patient probably bled half of his volume and the patient might be in hypovolemic shock and sometimes it might be too late. We also understood that bleeding complications were correlated with very poor outcomes, in the short and the long term, especially in patients who were undergoing PCI or had other co-morbidities.

A landmark situation was a patient where we had to use a vascular closure device. The ones that I was most familiar with were the Angio-Seal and the Perclose device. We had had a complication at UNC with a Duett device, which consists of a balloon occluding the femoral artery, and then a small injection of thrombin to seal the vessel. But there was a spill of thrombin into the femoral artery, and the patient had to undergo peripheral thrombolysis to reperfuse the lower extremity that was affected. So that was one complication that had not occurred to me.

But then I had another complication that really upset me: an infection of a Perclose suture. The patient had to go through significant pain and suffering, had to go for surgery, remained with chronic pain and had to receive long-term intravenous antibiotic therapy to treat an infected pseudoaneurysm.

It was then that I decided enough was enough!! I had to find a safer way to deal with these patients.

    Mauricio G. Cohen, MD, FACC
Mauricio Cohen, MD, FACC

At the same time, I was enrolling patients in a study looking at the pharmacokinetics of a IIb/IIIa agent in morbidly obese patients who weighed more than 275 pounds. Because I was very adamant about enrolling patients in this study, I said, “I'm going to cath all these large people who weigh more than 275 pounds.” So then I decided that, if I'm going to cath them, I had better find a safer way to do it.

So I refreshed the things I had learned initially in my training in Argentina, and started to explore the different technologies for access. I went through the process of teaching myself, and reading throughout the literature on how to perform these techniques safely, and what are the different challenges that you face. Then I attended a transradial course by Dr. Tift Mann and that was very helpful. Then I just started doing it.

Q: Did you have any problems initially when you started using the transradial approach?
Dr. Cohen: It especially seems to happen in this country, every time you introduce a new technique, or you say you're going to do something new in the cath lab, you start meeting resistance from the cath lab staff, because some of them feel that it's slowing the flow of patients. Of course, there's always a steep learning curve, and this curve has been very well described for transradial access. So it takes time before you find the optimal way of dealing with access, the optimal way of dealing with different positions on the table, different way of sitting up the table. But slowly, as I was getting more confident with the technique, the staff in the cath lab and my peers started to realize that actually transradial is a great technique, that patients have very few complications related to access, that patients really enjoy it, especially those who are morbidly obese, those who have significant back pain, or who cannot lay flat for prolonged periods of time. And slowly what started initially as just a clinical trial recruiting large patients, granted me the referral from all my peers to do all large patients.

Q: So when they had obese or large patients, they sent them to you?
Dr. Cohen: They sent them to me. And then afterwards, after the trial ended, the referring physicians and the patients were so happy because of low incidence of complications and patient satisfaction, that whenever a physician in our outpatient clinic decided to cath a large patient, I would get an immediate referral for transradial.

Q: So initially you had learned it a little bit in Argentina?
Dr. Cohen: I'd seen it in Argentina. I’d always had it in the back of my mind, and I was wondering why American physicians were not doing it. At the same time you saw all the French, Canadians, Spaniards and other people in the world that were huge fans of this radial vascular access technique. And now everybody's coming to realize that this may be the way to do cardiac catheterization in the future, because you are avoiding bleeding outcomes that can actually take the life of the patient.

The other thing for me was coming to realize that vascular closure devices are far from ideal. They do not decrease the complication rates. They decrease the time to patient ambulation, but they change the nature of the complications. They are different complications. That infected pseudoaneurysm, that really put a dent in my cath experience and that prompted me to find a safer way to deal with vascular access.

Q: Do you have any tips and tricks to share?
Dr. Cohen: The trick is to have a good and supportive environment. I think that doing your homework is very important, so you need to read the literature, look at other peoples' complications and have a good background reading.

Arm Board Support
Arm board support for cath table
    Then I think it's very important to have a comfortable set-up in the room, using a board. A good support for the arm, a good support for your equipment by the side of the table, is important -- using a board like we use in our cath lab, and using adequate vascular access technology. I think that the new short hydrophilic-coated sheaths, I'm using an 0.21 wire, has made a difference to me, has facilitated access significantly. Then people argue about the one-catheter versus the two-catheter approach. The one-catheter approach with, for example, a Kimny catheter or a multipurpose, is a little more involved, and in the training program that didn't work as well because in the end I always have to step in and manipulate the catheter myself.

So I think that the intermediate approach is to use Judkins catheters, for example JR4 or 5 for the right coronary artery, and a JL3.5 for the left coronary system. You always need to approach the easier patients, start easy, with large, young and male patients because they're more likely to have larger radial arteries and be complicated less often with spasm. So if you start feeling comfortable, the way I started with large patients who have large arteries, soon you will be hoping to meet the challenge of doing normal-sized people, females, then moving to older people who may have tortuosity in the subclavian arteries and develop experience on how to navigate the difficulties when accessing the supra-aortic vessels with the catheter.

Q: One of the objections I've heard is that you can't fit all different kinds of equipment with radial access because of the smaller size catheter.
Dr. Cohen: I think that's changing. It depends on the experience of the operator. If the operator feels confident enough that he can get all the difficult anatomy, including bypass patients with previous CABG, it's up to the operator to decide that. So in many circumstances you may not be able to do kissing stents or advance two stents into the same vessel through the catheter, because you may need at least a 7F catheter, or you may not be able to use a larger Rotablator burr.

But the thing is, you do these procedures only in the minority of patients. Most of the patients will be well served by a 6F catheter and a simple intervention. And you can still do a kissing balloon with a 6F approach. Here at UNC we have approached very challenging anatomy and we have rotablators, rotational atherectomy, we have complex bifurcation lesions, we have chronic total occlusions, and it's a matter of feeling comfortable. I think that those fears are just selected to a very small minority of patients, and in any case there's no harm done by accessing the radial. You can always stage the patient and bring them back and do transfemoral access.

Q: What about the other complication that sometimes occurs, which is vessel spasm.
Dr. Cohen: Spasm has been one of the major complications initially, when we did not understand very well or we did not have the right equipment and we were in search for the right spasmolytic drug cocktail. In my current practice, I only use 3 mgs of verapamil and I'm a little bit cautious in patients with low ejection fraction. Other people are using nitroglycerin, lidocaine and verapamil. Other people I know are using other calcium channel blockers.

We do not see spasm as a significant complication, or a frequent occurrence, at least in my practice. With the use of short hydrophilic-coated sheaths, and small catheters, we can always overcome the problems. When I approach patients, I always tell them that radial access is usually more involved because you need a little bit more manipulation, and in a certain number of patients they may experience pain as a result of vasospasm. I tell the patients this is somewhat unpredictable. But, if this happens during the case, the trade-off is that they actually are able get up after the procedure and walk out of the room, being able to be independent going to the bathroom and not having to wait and lay flat for hours after a femoral sheath is pulled. So I don't think radial spasm is that much of a significant problem.

Q: In terms of fellowships it’s very important to introduce fellows to this technique early on.
Dr. Cohen: Absolutely. Our interventional fellow that is graduating this year, he's pretty proud about it. He's extremely skilled and he has naturally good hands, but he's proud about being able to go and offer this to the practice where he's going to join.

This additional service to the patients he will be seeing, I'm sure, will result in referrals specifically for him to cath because he will be able to offer transradial access.

    University of North Carolina School of Medicine
University of North Carolina
School of Medicine

Q: It seems that the advantages are so clear, more patient satisfaction, less bleeding – what about nerve trauma in the femoral approach?
Dr. Cohen: Usually it goes away, but in a few cases it won't go away. The beauty of doing transradial access is that there are no nerve structures adjacent to the radial artery. The chance of injuring a nerve structure is almost nil.

Q: You've made a tutorial slide show about radial access. How do you use it?
Dr. Cohen: Actually, it's funny because in our cath lab we have a significant turnover of staff. So every day you turn your head and you see a new tech or a new nurse. So every day was like starting over again, and it was an endless job of training and teaching how I want the table set, how I want the arm board set, and it was frustrating.

Transradial Technique Slideshow
Click to View Dr. Cohen's
Tutorial on Transradial
Access (Flash required)

So I decided to bring my camera, ask permission from the patient, and start putting together a short tutorial, so if the staff has a question, I say “go and look at my slideshow and if you have questions, ask me.”

I developed this slideshow as an educational tool for the staff and also the fellows. And the fellows like it. And I've been pleasantly surprised, because every time I say “now we're going to do radial,” the fellows, if they're not that familiar with the technique, they are able to go online, look at the slides, and then they feel more confident when scrubbing in the case. Sometimes when I like to challenge them a little bit, I say “did you look at my slides? So why are you asking this question?”

The other thing that those slides help with is the nurses in the cardiology unit. Because, at some point, patients who had the radial approach started to come back from the cath lab walking and going to the bathroom. And the nurses were completely clueless. They had always cared for patients who had had the femoral approach. They knew that these patients needed to lie flat, could not get up, or they’d be at risk for bleeding.

But then the radial patients started to come with only these little bracelets on their hands! So the nurses worked with me and we developed an educational slideshow for them as well. We’ve also developed a manual of policies and procedures in the cath lab.

Q: Thank you Dr. Cohen. We are making your slideshow tutorial available online for those interested in the details of the radial approach. Thank you again for your time.
Dr. Cohen: You’re welcome.

This interview was conducted in March 2008 by Burt Cohen of Angioplasty.Org; page last updated on October 6, 2010