Guest: Dr. Christopher D. Nielsen - Director of the Cardiac Catheterization Laboratory.
Host: Dr. Pamela B. Morris – Cardiology
Dr. Pamela B. Morris: Hi! I am Dr. Pamela B. Morris and you are listening to Heart Sounds. I am talking today with Dr. Christopher D. Nielsen, who is director of the Cardiac Catheterization Laboratories at the Medical University of South Carolina. Welcome Chris.Dr. Christopher D. Nielsen:Thank you.
Dr. Pamela B. Morris: We are talking today about different types of procedure that might be used to open up blocked arteries and first I would like to talk about the difference between the old balloon angioplasty and what we now call stent placement.
Dr. Christopher D. Nielsen: When there are blockages with plaque in the arteries of the heart, there are several ways now that we have available to open up these blockages. We used to use mostly balloon angioplasty and what that does is we feed a small balloon down into the artery and push the plaque out of the way and then remove the balloon. That worked very well, but the problem with that is that sometime that plaque could just fall back into the lumen and narrow up the artery once again. What stents have done for us is a stent is like a small metal mesh tube that is placed in the artery and pushes the plaque out of way and holds the plaque out of the way and doesn’t allow it to come back in and cause blockage again. Now that occurs most of the time that the blockage does not occur again, but occasionally these things can narrow down once again.
Dr. Pamela B. Morris: Now, am I to understand then that neither of these procedures actually removes the plaque from the artery?
Dr. Christopher D. Nielsen:That’s correct. Most of the procedures that we do in the artery merely move the plaque out of the way, push it out of the way, or hold it out of the way as a stent does and really doesn’t completely remove the plaque. Now, there are few a procedures that are used, but are much more rare where we actually remove plaque from the artery.
Dr. Pamela B. Morris: Now, when would you decide to go in and actually remove the plaque and I believe that’s called an atherectomy, is that correct?
Dr. Christopher D. Nielsen: That’s correct. There are several types of atherectomy. There is rotational atherectomy, directional atherectomy, laser atherectomy where we actually remove the plaque and really what we found over the years is that removing the plaque is not the most important thing especially with a stent placed when we can open up the artery with a stent that works just as well, just by pushing that plaque out of the way and holding it out of the way, but it works just as well as it does when we actually remove the plaque.
Dr. Pamela B. Morris: Now the old balloon angioplasty you said that there was an incidence that would re-block again and how frequently did that occur?
Dr. Christopher D. Nielsen: With balloon angioplasty, it was about 40% of the time those would narrow up again over the course of the first several months. Now, obviously this was a major advance because before that all we had was bypass surgery and now all of a sudden we have something that would help the majority of people, 60% of people. So, if you were in the 60% that it didn’t narrow up that was a good thing however, if you were in the 40% that it narrowed up over a few months that was a bad thing.
Dr. Pamela B. Morris: How have these stent changed those statistics?
Dr. Christopher D. Nielsen: Once stents came along these decreased the risk of narrowing down the artery again down to about 10% and that was very good. So, if you were in the 90% that didn’t narrowed down obviously you were very happy, but if you were in that 10% you still could potentially narrow down that artery and require further procedure.
Dr. Pamela B. Morris: That’s a pretty dramatic difference from a 40% re-blockage rate down to 10% a re-blockage rate. Now, I understand there are two different types of stents that our listener may have heard off before.
Dr. Christopher D. Nielsen: Right, the original stents that came out were just made out of metal, we now call those just bare metal stents and over the years we figured out how to place medications on those stents to take the risk of a stent narrowing back down even lower. Obviously, again if you were in the 90% that the stent does not narrow down that’s good, but if you are in that 10% then obviously you are going to need repeat procedure. The drug coated stents; they are coated with a medication that prevents scar tissue or lessens the chance of scar tissue from forming inside them and those actually take the risk of these things narrowing down to in the 2% to 5% range.
Dr. Pamela B. Morris: There are two different types of drug-eluting stents, how do you choose one or the other?
Dr. Christopher D. Nielsen: There are two commercially available drug coated stents right now, but there are probably another two or three that will be released on the market in the next year or so. The two that are currently available are completely different drugs that work by different mechanisms, but remarkably have very similar rates of re-narrowing and so often times we choose the particular stent that we need to use just based on the length and the size that we have available.
Dr. Pamela B. Morris: Chris what types patients are most appropriate for placement of a stent?
Dr. Christopher D. Nielsen: Generally, the first step; when a patient has chest pain that comes from the heart and that is called angina or some people call angina and when they have chest pain that is related to the heart; the first thing that we always do is medical therapy. There are various medications that we use. Some of those are blood thinner medicines, some of those decrease the heart rate, some of them decrease the blood pressure, and some of them are for cholesterol, but the first step is always medical therapy. If medical therapy has been optimized, so they are on the best group medicines that they can be on then often times we will do a heart catheterization to see if there is any areas of specific blockage that needed to be treated in a more aggressive manner. Obviously, if we have multiple severe blockage in multiple blood vessel, sometime these requires bypass surgery to completely open up all of those arteries, but if there are blockage in one or may be just a few areas of the artery, then often times we can take care of these with the balloon angioplasty or the stent.
Dr. Pamela B. Morris: I understand that now it is possible; however, to place stent in more then artery or in more than one location successfully.
Dr. Christopher D. Nielsen: That’s correct. Often we are available to place stents in multiple arteries now. It used to be said that patients that have blockage in all three of the major arteries that those were usually patients that needed surgery or bypass surgery; however, nowadays we can place these stents at very low risks and at very high success rates in multiple arteries and people do just as well as with surgery.
Dr. Pamela B. Morris: What would happen if a patient who has stents in place ultimately does require bypass surgery? Are there any problems then?
Dr. Christopher D. Nielsen: When we place stents in patients, it rarely causes any problems for future bypass surgery. Essentially placing a stent or multiple stents in the arteries does not rule out a future bypass surgery.
Dr. Pamela B. Morris: Well, this has been a very interesting discussion to help us better understand the role of stents in managing heart pain or angina. Thank you and we will come back in a later discussion to talk about the long-term management of stent patients.
Dr. Christopher D. Nielsen: Thank you.
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