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Transradial Approach Interview Series
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Ferdinand Kiemeneij MD PhD, Part One
Ferdinand Kiemeneij, MD, PhD, OLVG, Amsterdam
Ferdinand Kiemeneij, MD, PhD
On the occasion of the 20th anniversary of transradial intervention (TRI), Angioplasty.Org talked with Dr. Ferdinand Kiemeneij, "the father of transradial intervention" and interventional cardiologist at Onze Lieve Vrouwe Gasthuis (OLVG), Amsterdam, The Netherlands. We covered a wide range of topic regarding TRI, presented here in two parts:
  • Part One discusses how and why he originally developed the technique, how equipment changed to make TRI easier and safer, how and where it has been adopted, and some thoughts about complications, specifically radial artery occlusion (RAO);
  • Part Two continues discussing RAO and how to avoid it, compression techniques, and Dr. Kiemeneij's vision of the future of TRI and what needs to happen for its ultimate worldwide acceptance as the default approach for catheter-based intervention.
Dr. Kiemeneij first began doing angioplasty and stent placement from the wrist in 1992 and has been teaching, lecturing and doing live case demonstrations around the world ever since. He travels regularly to India, Japan and China and recently received a B.A. in sinology. Last year, in celebration of the 20th anniversary of TRI, he created an app for the iPhone and iPad, called TRIbune, which can be downloaded free from the iTunes store. He is active on Twitter and can be found at @ferdikiem. (Update: In 2013 Dr. Kiemeneij moved from OLVG to Tergooi, outside of Amsterdam. In 2016 he published "InterZENtion: Transradial PCI as an Art.")

Q: When did you first think of doing coronary interventions from the radial artery?
Dr. Kiemeneij: During the very early days of coronary stenting. The biggest advantage of placing stents for me had nothing to do with the reduction of restenosis but actually to have a safe bailout mechanism just in case your coronary artery dissected during balloon angioplasty. In our hospital, that meant we had to have actual surgical standby during our PCIs in those years. I'm talking about 1986. Surgical standby was a very expensive thing to have: an actual team, and a bed, and an operating room, all waiting for your possible problem. That limited our output.

Then I started to discuss with Patrick Serruys the use of the Palmaz-Schatz stent not as a bailout device, but as a device to prevent restenosis. That was actually the premise of the BENESTENT study. So we started to stent on a more regular basis, but we had a problem with those fully anticoagulated patients who had Coumadin, dextran, heparin, persantine, aspirin. Everything we could find to block the coagulation system, we just gave to the patient. And we had the groin prepared with an 8F sheath, sometime 9F even. So we had this difficult balance between sheath removal and hemostasis and that could last maybe a day, two days, sometimes three days, before we had the proper balance between the patient being adjusted on Coumadin, we could lower heparin, and then we could retrieve the sheath.

But despite all those precautions, we saw groin hematoma develop. These were very hard to handle under anticoagulation, especially in the more obese and older patients. Usually a groin complication also resulted in a coronary complication because you had to reverse anticoagulation and the patient was hypotensive. Also in that time the stents were not properly deployed; we did not do routine ultrasound, IVUS, which was Antonio Colombo's great contribution. So, actually, we lost some patients' lives.

The Board of Directors in my hospital urged me to find some solution for this because otherwise I had to stop the whole stent program. But then, as a gift from heaven, came Campeau's paper in 1989 in Catheterization and Cardiovascular Diagnosis: 100 patients that he had angiographed via the radial artery with 5F catheters. I'd never heard of that before, so when I read that article, actually a very modest and short article, I was impressed. If you can reach the coronary artery via the radial artery, and why shouldn't you, instead of just injecting contrast, also advance a wire and a balloon and maybe a stent; that would solve the whole problem [of hematomas] just based on the anatomical characteristics of the radial artery.

Angioplasty.Org Image

I took the Grey's Anatomy from 1948 from my father and I saw a couple of pictures, those beautiful drawings, of the forearm, the radial artery, and you could see that based on the characteristics of the radial artery, it is in effect surrounded by bony structures, together with the Palmar arches.

Altogether that meant for me this is a safe place and, if you have bleeding, it's easy to control. You can just remove the sheath immediately, and if something happens the patient can even handle the problem himself. In the groin, if you lose blood, it takes half an hour or an hour before you notice. But in the wrist, it's immediately evident.

So that actually was kind of a dream that I had based on this publication. Wow, if we have stents that are compatible with the radial artery diameter.... Don't forget at the time we had a stent delivery system from J&J that was quite a bulky device - so we had to rip off the stents from the balloon and crimp them on smaller balloons, and it took a couple of years before we got 6F guides available and that was in '92. Then we started to do the first PCIs from the radial artery, but the reason was to reduce bleeding concerns during coronary stenting.

Q: So the initial impulse to use the radial artery came out of a concern for safety?
Dr. Kiemeneij: Yes, absolutely. Safety and comfort.

Q: You were talking about equipment and the fact that the catheter systems were so bulky. Part of the spread of the transradial approach, as well as other interventional procedures, has to do with better equipment.
Dr. Kiemeneij: Having a 6F guide was number one, because radial artery diameter, compared to the femoral, is a completely different story. In radial we're not 8F compatible. We had to have 6F guides.

At that time, 6F guides were absolutely not popular because during stenting you really needed to have enormous backup support of your guides. Also, visualization and retrieval of the stent systems. Those stents were manually crimped on the balloon. Suppose your stent failed to open the lesion? Then you had to draw the whole system back into the guide. With a 6F guide, it easily could happen that the stent slipped off the balloon, leaving the undeployed stent in the coronary artery. So, all those issues together, backup support, the small inner lumen, the risk for stent loss, gave rise to a discussion whether or not to use 6F guides for stenting at all.

But 6F guides became better and better. Their inner lumen became better, there was better backup support, you had dedicated catheters for radial. Softer tips, more flexible tips, stiffer primary and secondary curves to increase support, etc. So there was a lot of work spent in developing better guides. That's one.

Then, of course, the stent delivery systems were getting better. In the early years you would just buy a box of Palmaz-Schatz stents without balloons, just to crimp them on your own balloons. But later, you had stent delivery systems without the sheath, just the stent crimped on the balloon, done in the manufacturing plants. So we did not have to do that ourselves, with all the limitations. And stent balloons were getting smaller and smaller. So altogether it became easier to get stents implanted through 6F guides.

Q: Tell me about the first transradial PCIs?
Dr. Kiemeneij: It started in '92 and ended in '94. I call that "TRI: The Beta Version." It was just the tryout phase, not suitable for public. In those two years, we just used what was available for the femoral approach: needles, sheaths, etc.

But later in '94, we got the first international exposure of TRI via a beautiful live demonstration of Jean Fajadet, who just a couple of weeks before visited our hospital and saw the patients walking from the table immediately after stenting, and said, "That's something I want to show in two weeks during the TCT!" I was very nervous about that because I had two years experience and he had no experience at the time that he proposed this. But he did a beautiful case two weeks later from Toulouse, and he initiated a lot of international attention.

From then on, the medical industry began to focus on dedicated TRI equipment. Terumo was very early, also Cordis and Cook and Arrow are some early names that developed dedicated needles, dedicated sheaths, and that's an improvement which is still continuing.

Drs. Kiemeneij, Gao and Saito
Drs. Kiemeneij, Gao and Saito at 2007 Great Wall International Congress of Cardiology in Beijing

But I think that the latest developments are found in the Slender Club, which is a group of Japanese TRI adepts. They're quite fanatic in downsizing and miniaturization to the absolute limits, 3F coronary angiography, sheathless 4F PCI. Saito calls that "Virtual 2F." And this is a very active group: they meet several times per year and they challenge each other to show the most complex cases via most downsized systems. You can't imagine the complexity of the cases that they are doing with miniaturized materials, and I have the impression that the Japanese companies are very actively developing materials for this Club. So, from that corner of the world, we are getting from Japan, I think, the best materials at the moment, the best guides, the best wires, the best balloon systems, the best stent systems, it's really quite impressive what they are doing.

Q: Speaking of international spread, while the U.S. is gaining in acceptance of transradial, it's still well behind everybody else.
Dr. Kiemeneij: It took a long time before 6F guides were generally accepted in the U.S., while in Europe everyone was already actually working with 6F. I don't know exactly why. With everything we have today, you can have over 90% transradial practice if you want. But it's not only in the U.S., also Australia, New Zealand, there are also European countries that are far behind -- Switzerland, Germany until recently-- so there's an enormous variability in the application of transradial approach.

Q: We talked about the wide variability in where TRI is practiced. Why is that?
Dr. Kiemeneij: I think one of the most important reasons is that you need to make TRI a routine practice in your clinic, otherwise you're not going to be very successful for you or your patients, and your nursing staff is not going to like it.

It's not easy. Femoral approach is technically a lot easier. Personally, I was surprised by the problems you could encounter during a transradial PCI. Getting to the coronaries is sometimes already quite a procedure. You have to cope with tortuosity, maybe some narrowings, calcifications, spasm. But, with routine, everything gets easier, and a fast and a smooth procedure will be noticed by the patient.

I understand that in the United States there are some very small practices that do 50 or 100 PCIs per year. I don't think you can ever be successful if you are doing a few PCIs per year by the radial. I'm sure of that.

Q: But once TRI becomes easier to do, when it becomes routine, isn't it also safer?
Dr. Kiemeneij: Now the results of the RIVAL study, the RIFLE-STEACS from Italy, the MORTAL study from David Hilton in Canada, and more and more data are pointing towards mortality reduction, especially in transradial PCI for acute coronary syndromes. And if that's true, if you reduce mortality, we're not talking just about patient comfort any more, which is a relatively soft endpoint, but we are talking about very, very hard data. So, that's going to be the discussion sooner or later. "Why didn't your doctor do a radial procedure, because we all know that it's safer?" Suppose that's going to be the argument? That will actually change practice. But, those are hard scientific data that, according to me, still are not there, but I'm sure they are coming, and sooner or later we'll know that.

Q: I'd like to talk about complications. Of course, there are well-documented complications with the femoral approach -- this is unfortunately one of the most popular topics in our Patient Forum.
Dr. Kiemeneij: Yes. Everyone forgets about the complications that they have ever made. Here in Holland you have discussions, "Well, I never see problems with femoral approach," but in the meantime, there ARE problems.

Q: A lot of times, they don't see them, because the complications are dealt with by someone else, for example the Emergency Dept.
Dr. Kiemeneij: Yes, yes that's true.

Q: What's the biggest complication in radial artery access in today's practice and what's your advice on avoiding it?
Dr. Kiemeneij: There's a difference between the biggest complication and the most frequent complication. There are common ones and rare ones, but rare ones can be very dangerous. For example, very rare, but still a complication, is inadvertent access and perforation of the vertebral artery with a hydrophilic wire. Maybe mediastinal hematoma, that can happen. It's not that this doesn't happen with femoral approach also.

Dr. Kiemeneij in Cath Lab
Dr. Kiemeneij in Cath Lab

But I think personally the biggest enemy for TRI is radial artery occlusion. Suppose everyone is going to take the radial artery as the default route, and patients are coming back 2, 3, 4, 5, 6 times for staged procedures, coronary angiography, repeat procedures, a control, another vessel. So the radial artery is used multiple times. That might result in radial artery occlusion in the end. If you don't take good care of the radial artery, then maybe ten years from now, in an important percentage of your daily interventional practice, you might see patients with occluded radial arteries, so you have to take another artery, or the left radial artery, or even the groin. I'm not saying that is going to happen, but it is a concern.

I don't know if radial artery occlusion is underreported, we thought it was around 3%. Early occlusions were higher, around 10%, but a lot of radial artery occlusions recanalize spontaneously. Still, 3% is 3%, and if you don't take proper care, that might be higher. So if we want to continue to give the safest strategy to the patient, which in my view is still TRI in terms of prevention of bleeding, then we should guarantee to patients that they end up with a patent radial artery; the artery is theirs, it is not the doctor's! There are ways to prevent radial artery occlusion, proper heparinization for example, is one -- also good hemostasis technique, it's called patent hemostasis, where you do not block the radial artery for a long time just to get hemostasis, but gentle compression, everything gentle.

Q: I made up a rhyme about that: "Too Long, Too Strong For Radial is Wrong."
Dr. Kiemeneij: That's true. That's the whole story, actually.

This interview was conducted by Burt Cohen of Angioplasty.Org.