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Transradial Cardiac Catheterization: When, Why and for Whom is it an Option?

Melanie (Host): Since the first cardiac catheterization in 1929, the procedure has continually evolved with advances in understanding, capabilities, and ease of operation. My guest today is Dr. Robert Lager. He's an interventional cardiologist with MedStar Heart and Vascular Institute. Welcome to the show, Dr. Lager. Why don't we start by having you give us a little physiology lesson about the heart and how it works?

Dr. Robert Lager (Guest): Thank you for having me today. The heart is, obviously, an important organ within the chest and the heart has several functions but the most important function for the heart is as a pumping organ. The heart has several chambers: two on the left side of the heart, two on the right side of the heart. These chambers are muscular chambers, made of muscle, and they basically propel blood through the chambers either to the lungs themselves to gather oxygen or, once that's been gathered, back to the left side of the heart and over to all the organs: the brain, kidneys and abdominal organs etc. The heart actually has several systems built into it including an electrical system which controls the rhythm of the heart and a plumbing system which basically carries blood to the heart muscle itself via the coronary arteries which run along the surface of the heart muscle and then dive in deeper as it supplies blood flow and oxygen to the heart muscle itself.

Melanie: It's a fascinating organ. How do you doctors get a good look at the heart to tell us what's going on?

Dr. Lager: It really depends how or rather what we'd like to see. There are many different ways to image hearts, many different ways to evaluate heart. Some are electrically using EKGs, and some are imaging techniques such as CAT scans or MRIs to look and characterize the muscle of the heart. Then, some are to look directly at the heart arteries and we use catheters to do that. We usually use thin catheter tube to inject x-ray dye into the heart arteries which allows us to look at the arteries themselves and decide whether any problems such as narrowing or blockages in the heart.

Melanie: If this gives you a good robust picture of the inner workings of the heart and how it's working, who would be a candidate for this? Who would you decide needs this type of catheterization?

Dr. Lager: Catheterizations themselves, cardiac catheterization are done specifically to look at patients who we suspect may have heart artery narrowing or blockages. Those patients often present with either classic symptoms such as chest pain with exertion, shortness of breath, or related symptoms such as shoulder, jaw, or back discomfort. The patients who have symptoms which occur with exertion and a more stable pattern, we often will evaluate with things like stress tests first to see whether there is actually a suspicion of a blockage or narrowing in a heart artery. There are also groups of patients who come in with these types of symptoms suddenly, unexpectedly, at rest, which are more heart attack like symptoms and those patients are most frequently brought to cardiac catheterization immediately without any delay, if possible.

Melanie: Dr. Lager, what is cardiac catheterization?

Dr. Lager: In a catheterization procedure, we bring a hollow tube catheter through an artery either from the groin or the wrist up to the heart. We position the catheter opening right at the opening of the main arteries of the heart which start just above the heart and then run along the surface of the heart. Then, we inject x-ray dye contrast into the heart arteries while we're taking x-ray pictures, fluoroscopy, from outside the chest. Therefore, we see as the x-ray dye courses through the heart arteries, we can see whether or not there are any narrowing or blockages in the arteries themselves. So, the first key to doing this procedure as you alluded to is selecting the right patients, patients who really should be having these procedures. Then, once we've decided that a procedure like this needs to be done, then we decide how to do it. Historically, actually, I think you mentioned that this procedure was first done in 1929. This was actually done by a physician in Germany who actually accessed his artery in his arm, right at the level of the elbow, and brought a catheter up and took measurements with that catheter on himself when he walked from his office to the radiology department to measure the blood pressures in his heart and lungs. So, subsequently, and all through the late 70's and early 80's we started to do these procedures more typically through the groin, and that was because we needed to use larger catheters and as we started to actually develop procedures to fix heart arteries, that is to say angioplasty, we first started with balloons to do that in the ‘80s, and we use fairly large tubes to do that, too big for anything that would accommodate through the arm themselves or at least through the smaller arteries at the wrist. So, we would either do what was called a “cut down” which meant exposing the arm artery right around the level of the elbow or, as we moved to the groin, it was actually easier for us to do it through the groin, and that was called the “transfemoral approach”. So, from the 1980's onward, at least in the United States, well into the 1990's and even in to the 2000’s, the vast majority of procedures we did were from the groin, the transfemoral approach.

Melanie: What is trans-radial catheterization?

Dr. Lager: Many doctors, especially in Europe and in Asia, began to realize that we could start to do these catheters from the wrist. And, this really took off in places outside of the US much earlier. So, that many European hospitals and physicians, and many hospitals in Japan and other Asian countries were doing procedures from the trans-radial approach, that is from the wrist, long before we talked about doing it here in the US. The reason why that was started to consider is, one, the catheters got smaller. So, we didn't need to use such big catheters to get in the arteries. Two, the wrist itself is a very easy place to access the arteries, and that's because it is immediately against the bone so we can see the artery, and can control any problems of bleeding very easily whereas, in the groin, the arteries are very large and it's very deep, and we often can't see exactly what's happening at the artery level either when we're working or after we're working and take the tube out. So, there became a lot of excitement about this procedure because it was clearly safer in relation to bleeding at the access site, whether that was the growing or the wrist. As we gathered more information about trans-radial procedures, we started to learn that it might have benefits in specific groups of patients who are at highest risk for bleeding. Not to mention that from a patient comfort perspective, the trans-radial approach is exceedingly more comfortable for the patient. Whenever we've done studies to look at a patient, when a patient has had a procedure both from the groin and later from the wrist, if you were to ask them, “How would you like the procedure done if you had to do it again?” Ninety percent of them said they'd rather do it trans-radially, through the wrist. It became a growing momentum about reasons to use the wrist, and those include safety reasons and comfort reason. We've seen in the United States, finally, a major push to start using the trans-radial approach over the last five years. Although it is still not the majority procedures done in this country, most young cardiologists are being trained to do the trans-radial approach as their default approach.

Melanie: Dr. Lager, are there some patients for whom this is not an option, maybe the elderly whose skin might be extra thin at that point, sometimes hard to find an artery in their wrist area? Are there some people that are that just can't get this procedure?

Dr. Lager: There are. One of the interesting paradoxes of this area is that the patients sometimes who are the most difficult to do trans-radially are actually the patients who benefit the most. Your example is a great one, let's say a very elderly patient who's very frail and small and thin with low body weight often has much more fragile blood vessels, small wrists, small arteries. They are actually the same patients who have the highest bleeding risks when you go from the groin. They also, as you get older, can develop a lot of twists and turns in the arteries, we call that “tortuosity”” and that can be a very important problem from us as we come from the wrist. It's quite a ways to go up, down, all the way up to the shoulder and then back out of the heart. As we get older, those arteries can develop lots of loops and bend, and sometimes it's just not even technically possible to get a catheter to track around all those loops and bends. So, elderly patients are one group that truly benefit very much from the trans-radial approach but also maybe one of the more difficult groups to perform it in. When you look at big studies to show what are the primary failure rates for trans-radial, probably I'd say the most typical one would be patients who had bypass surgery before, coronary artery bypass surgery, open heart surgery, where the surgeon will sew bypass grafts into the aorta and then bring those down to the native heart arteries. Sometimes it can be difficult to take pictures of those bypass grafts from either the groin or the arm. We often come into more technical issues trying to do that from the arm than we would from the groin. That being said, I still personally do the vast majority of my procedures from the wrist for patients who had bypass surgery, and the vast majority of them are successful. There are groups of patients who may have had the artery actually harvested for bypass surgery. For that, they use the radial artery for a bypass, and, therefore, obviously we can't use the wrist for that procedure. There are patients who are on dialysis and have arteriovenous fistulas--these are manmade connections between the vein and artery in the wrists or arm that are used for dialysis—and, therefore, we really stay away from those because they can be very fragile and we don't want to do anything to jeopardize that longstanding fistula which is used for dialysis. Other than that, occasionally we'll see a patient, where we do check to see if there's good blood flow to the hand from more than one artery in the wrist, although that's somewhat controversial. In other places in the world, that's not even checked anymore, but in the US we tend to check on that. Sometimes if we see that the other artery in the wrist that we're not using, if that's very small, or doesn't really supply much of blood, then we may avoid going in through the wrist altogether. So, we do still check that routinely in the United States. Outside of the US, most people think that's probably unnecessary. Those really are the typical stories of patients who, for whatever reason can't undergo trans-radial. It's a very small percentage of patients who cannot be counted for trans-radial approach.

Melanie: Dr. Lager, in the last few minutes, give your best advice as if I was a patient sitting across from you in your office asking you questions about catheterization in general, why I might need it. Tell them what you tell them every single day about the ease of this procedure and the better outcomes?

Dr. Lager: We know that for many patients once we've made a decision and that's a key part of this, as I mentioned, is the decision to perform a cardiac catheterization. Once you've made that decision and it's clear for clinical reasons that a catheterization is appropriate, our next decision is how to do it. We always have the two options of the artery in the groin, the femoral, or the artery in the wrist, trans-radial. For those of us who do these routinely now, the default position, the routine approach, should be the wrist. The reasons I mentioned were for patient comfort which is clear and incontrovertible, and not only the bleeding risks which seem to be lower at the access site for the wrist but, more recently, in certain groups of patients we've seen, for instance, those patients who come in with heart attacks where we have to give lots of blood thinner, their risk of bleeding is very high and those patients have actually shown a mortality benefit for trans-radial approach versus the femoral approach. Why is that? It’s because bleeding is such a major player in bad outcomes for patients with these procedures. We worry a lot about blood clotting, things that cause heart attacks or catheters causing clots, but, in truth, the bigger risk is bleeding. So, any approach that can lower the risk of bleeding can significantly affect the entire outcome of a patient who might otherwise have had a terrific result from the procedure but if they have a bleeding complication it could be disastrous. When I talk to patients in the office who are more elective, who are not in the throes of a heart attack, we talk a lot about the risks and the benefits of the procedure and clearly one of the major risks of the procedure is bleeding. We give blood thinners during procedures routinely and so using any technique that we can use to lower the risk of bleeding is one we should strongly consider as our default position. Secondly, as I mentioned from the comfort standpoint, there are so many of us that have bad backs, and the notion of having to lie flat after procedure for sometimes between four and eight hours after procedure is pretty daunting. Even when the procedure went great, you end up incredibly uncomfortable. In fact, every now and then, I talk to patients and say, "How was your experience the last time you had this procedure?" They say, "The actual procedure was fine but I was miserable for six hours lying flat after the procedure." Well, in this procedure, the trans-radial procedure, you can literally walk off the table if you wanted to. We tend to keep people at some bed rest for about an hour or two just to watch them after sedation is given but you can sit right up, you can eat right afterwards. You can be in total comfort instead of flat on your back, and that is something I don't think we emphasize enough when we talk about the trans-radial procedure is that comfort element, which can be the number one problem for most patients when they come through this procedure it's so much less of an issue.

Melanie: Thank you so much, Dr. Lager. That's really great information for listeners. You're listening to Medical Intel with MedStar Washington Hospital Center. For more information you can go to www.medstarwashington.org. That's www.medstarwashington.org. This is Melanie Cole. Thanks so much for listening.