Transcription:
Coronary Calcium Scan for Early Detection of Heart Disease Risk

Melanie Cole (Host): In the United States, the most common type of heart disease is coronary artery disease. For some people, the first sign of coronary artery disease is a heart attack, but a coronary calcium scan might just help you know your risks and allow you to take steps to improve your heart health. My guest today, is Dr. David Murdock. He’s a Cardiologist at Aspirus Cardiology. Welcome to the show, Dr. Murdock. What is a coronary calcium scan?

Dr. David Murdock (Guest): A coronary calcium scan – if you do a chest X-ray of somebody, you will see the ribs, and that’s because the X-rays easily identify calcium. If we do a CT scan of the chest and we course through the heart, we can pick up calcium in the coronary arteries. That’s sometimes the first signs of coronary artery disease, the most common killer of people in the United States.

Melanie: So, the scan itself – first of all, what are the benefits? When would somebody even be considered for this kind of a test?

Dr. Murdock: That’s a very, very good question. Considering that again, coronary disease is the number one killer; we know that there is various risk factors for that – diabetes, high blood pressure, family history, high cholesterol, etcetera. Those are all looking at risks for heart disease. This is actually telling whether you have the disease or not. What did all those risk factors do to you? The more calcium you have in your coronary arteries, the more likely you are to have a cardiovascular event. The other thing is also true if you don’t have coronary artery calcium – if you don’t have calcium in your coronary arteries, your chances of having a coronary event are very low, so it gives us information on both sides, whether you’re a low-risk or whether you’re a high-risk.

Melanie: How does the doctor decide, and who should get – if you’ve just spoken about some of the risk factors for coronary artery disease, and somebody might be at risk, is this a test that you would recommend for many people or only specific populations?

Dr. Murdock: Well, I think it should be more widely utilized. It’s generally agreed that it shouldn’t be used in very low-risk people – and I’ll tell you what I mean by that – nor should it be used in very high-risk people. It’s used to change therapy or make therapeutic decisions. If you have a very low-risk, their chances of having coronary disease are so low that it’s not likely that it’s going to pick up anything. Examples of that would be very young people – people who have no risk factors for heart disease or are less than age 40, their chances of having coronary artery disease is so low that we don’t generally recommend obtaining the coronary calcium scan unless there are some other concerns ongoing.

The opposite is also true. If you have very high-risk – let’s say you’ve already had a heart attack, or you have peripheral vascular disease, or you’ve had a bypass operation, we already know that you are in the high-risk group because you’ve already shown that and our treatment is going to be geared to a high-risk person already. It’s not going to give us any information that we don’t already know from you’re history.

Melanie: If somebody is in that risk population that you would consider this test, does it matter if they’re on a statin or if they have high cholesterol that’s already being managed, or if they have hypertension and you assume or think that they might have atherosclerosis or something?

Dr. Murdock: Right, this is a test for atherosclerosis. Sometimes, the very first signs are that there is some laying down of calcium in the coronary arteries. All of those things you mentioned are risks for atherosclerosis. This detects whether you have it or not and the extent to which you have it. It actually – there is no more accurate risk predictor of an event than the coronary calcium. It’s higher than – it’s a better risk determiner than high cholesterol or high blood pressure. It gives us more information than those things do.

I’ll give you an example. Yesterday, I was on call at the hospital, and I had a patient who came in, and he had been to his doctor’s with some atypical chest pain and the doctor who did his risk of cholesterol and high blood pressure and felt that his situation wasn’t bad enough to need a statin. Well, it turns out – he got cathed while he was in the hospital and he had severe, three-vessel coronary artery disease. The point is, the standard risk factors for him failed him. He wasn’t being treated aggressively, yet he was loaded with coronary artery disease. That would have easily shown on a coronary calcium score.

Melanie: Tell us about the test itself. What’s involved?

Dr. Murdock: It’s a very easy test. A CT scan – you basically lay on the table, and the CT scan goes over you and takes the X-ray images of your heart. It reconstructs them in three-dimensions and then determines the calcium in the coronary arteries. It’s automatic. There is a computer algorithm that quantitates the amount of calcium, and then you are compared to everybody else your age and sex in the database, which is huge – hundreds of thousands of people have had these done. That data goes into that database, and you’re compared to that database with respect to how much calcium you have compared to somebody else your age and sex.

Melanie: What do the results mean? Who reads them? Is this something that can be – when it’s being done, the radiologist or whoever is doing it tells you the results or is this something someone has to look at, it takes a little time, and then you get your results?

Dr. Murdock: A little bit of both. The CT scan – the computer algorithms will quantitate the amount of calcium, and it will tell where they are. Are they in the right coronary artery, the large artery running down the front of the heart, sometimes called the Widowmaker. It will tell us where they are and how much calcium, and that will generate a number – a total number that we call the coronary calcium score. Of course, the normal coronary calcium score is zero. Values above 400, for instance, are considered very high-risk – the same risk as if you’ve already had a heart attack that you might have another one. Those are called coronary equivalents. That is, you have the equivalent risk of somebody who’s already had a cardiac event. A coronary score of zero basically means we could not detect hardening of the arteries or atherosclerosis in you and that can help in the decision making too. We don’t give chemotherapy to people who don’t have cancer, for instance. Well, if you don’t have coronary disease or atherosclerosis, then the need to treat aggressively with statins isn’t there.

Melanie: So, that’s the first line. If you see this and they have a score obviously, above zero, or anywhere that you feel, Doctor, is high enough that treatment or aggressive treatment is required, then what? You start with statins and then discuss whether they’re going to need some kind of angioplasty or something later on down the line?

Dr. Murdock: That’s exactly right. Let’s say they have an elevated score and that puts them in the high-risk group. Well, the first thing – even if they don’t have symptoms, that doesn’t mean they don’t have a problem. That’s the unfortunate thing about heart disease is about 40% of the time, the first event is sudden death. If somebody has an elevated score, we may want to do a stress test on them then. That will uncover -- if they have significant blockages, that will uncover those. The stress test will become abnormal and that may lead to a cardiac catheterization demonstrating the extent of the disease and the need for either cardiac surgery or perhaps, a stent, or less significant disease that we might treat medically by trying to knock down the cholesterol as much as we possibly can – controlling the blood pressure, controlling the diabetes, should it be present – that sort of thing.

Melanie: So then talk about prevention for us in summary, Dr. Murdock. Give us your best advice as a Cardiologist, what you want people to know about the importance of asking their physician about a coronary calcium scan if they have any of those risk factors, and what you want them to think about when they’re thinking about diet, and exercise, and atherosclerosis, and preventing the calcium build-up in the first place.

Dr. Murdock: That’s a large question. [LAUGHING].

Melanie: I know. You can do it.

Dr. Murdock: Well, you mentioned most of the things right there. Again, keep in mind that we’re treating the most deadly disease known to America. It basically kills every other person in this country. Not now, but in your lifetime, we all die of something. That is likely the cause of death in almost half of the people in the United States – strokes, heart attacks, peripheral vascular disease, aneurysms, all part of the same process.

We know that there are a lot of risk factors that we can control. Weight is a big risk factor, and that determines whether we become diabetic. Plenty of exercises may help determine whether we become diabetic or not. So, adequate amounts of exercise. And of course, healthy eating. We know sugar is one of the culprits that we have in our country. That is one of the worst things for us. The amount of sugar we eat has gone up many-fold over the last hundred years. The sugar intake has gone up, pushing the problem with obesity and diabetes along with it. Healthy eating is a big part of it in that complex carbohydrates, making sure you have enough fiber in your diet, trying to eliminate a certain amount of red meats, trying to cut back on them – saturated fats. That all becomes important.

And then your blood pressure – we have ways to control your blood pressure. A lot of it will be controlled with simple diet measures, but if not, medications – there’s a lot of medications that are very effective, and they have been proven to reduce the chances of having a major cardiac event. All of those things need to be taken into account when we try to eliminate this process. We’ve done a good job. If you look over the last twenty or thirty years, the chances of dying of cardiovascular disease has continued to drop, so we’re making really good progress with what we’re doing. Unfortunately, that’s being negative to some extent now, by the obesity epidemic that’s hit America in the last twenty years.

Melanie: Well, it certainly has, and we can discuss that on another show. Thank you so much, for being with us today, Dr. Murdock. This is Aspirus Health Talk, and for more information, please visit Aspirus.org, that’s Aspirus.org, if you have questions about a coronary calcium scan. This is Melanie Cole. Thanks so much, for listening.