Host: Welcome to HeartSpeak Consult Live, a webinar created by Baylor Scott & White Heart & Vascular Hospital, Dallas-Fort Worth, and Waxahachie. This is an opportunity designed for primary care providers seeking treatment options for patients who may be experiencing a cardiovascular concern. Today's program, Cardiac CT for Primary Care, Coronary Calcium Scoring, and CT for Coronary Angiography, is presented by Dr. Jeffrey Shussler, Chief Medical Officer and Interventional Cardiologist on the medical staff of Baylor Scott & White Heart & Vascular Hospital, Dallas-Fort Worth and Waxahachie. During this presentation, Dr. Schussler will discuss the increasingly popular modalities of evaluation of the heart with cardiac CT. This will include screening asymptomatic patients with coronary calcium scoring and the use of CT coronary angiography to evaluate for symptomatic coronary plaque. The course objectives are: Identify the similarities and differences between CAC and CTCA, understand the indications and the contraindications to ordering these two tests, and basic interpretation of these two modalities.

And now, please welcome Dr. Jeffrey Schussler.

Jeff Schussler, MD, FACC, FSCAI: So we're talking today about cardiac CT, um, coronary calcium scoring and CT coronary angiography, and particularly as it pertains to primary care. Um, we're using these tests more and more to evaluate patients for coronary disease, and it's not just cardiologists that are ordering this.

There's quite a few primary care doctors that send people for screening, um, also for evaluation for chest pain. I have no disclosures.

And before we get started, uh, there was an interesting article that came out late May where they're actually just not just using CT scans to evaluate, uh, our patients, but they've actually used this to evaluate mummies. It turns out several thousand years ago, people died from lots of things, but one of the main causes of death was actually heart disease.

So they've taken mummies and scanned them with CT scanners. And much like you can use it to evaluate live patients, you can use it to evaluate mummies. And what they saw was quite a bit of coronary atherosclerosis. You can see this here in the scan of the heart and also plaque that was built up in the aorta and in other areas in the neck, for example.

So it turns out that this disease process that is the number one killer of people in the modern world was actually one of the same issues that they had to contend with way back 3,000 to 5,000 years ago.

We're going to talk about calcium scoring and CTCA, how they differ, how they're performed, a little bit about, a little bit about the cost, the radiation dose, and most importantly, indications and appropriate use.

This is the most important slide. It's kind of a summary of both of these modalities, and you can see calcium score on the left and CT on the right. The, the biggest differentiator is the, what they're indicated for. And for calcium scoring, it's really a test for screening asymptomatic individuals who have no known history of coronary disease.

So someone comes in, they're just worried about the risks, they may have family history and getting a scan to evaluate them for plaque. Whereas a CT is really a test that's used to evaluate for actual chest pain. The radiation dose is much less for a calcium score. And to put it in perspective, a chest x-ray is about 0.1 millisieverts, very low dose. It's usually one to three for a calcium score, much higher for a CT coronary angiogram, about five to 10 millisieverts. There's no contrast used for a calcium score, so you don't need an IV, you don't need to fast. For a CT coronary, you actually need an IV and you need to inject contrast, usually use about 80 to 120 cc.

So it's not great for people who have bad kidneys, um, but you know, it's, it's negotiable. Very cheap test. The calcium score is only about 80 dollars. It's not really paid for by insurance. Usually the CT angiogram is something that insurance will pay for, for the right indications. And then what you get is really an evaluation for the presence or absence of calcified plaque.

And if you have it, you're done. You don't need to do any further testing. Whereas with a CT coronary, since it's done for chest pain, if you don't have plaque, you're fine. But if you do have plaque, then you have to make a decision as to whether or not you need further invasive testing or just medications.

The screening criteria for calcium scores, we really think that men age 45 to 75, sort of the ideal sweet spot, or 50 to 80 for women, and that's if they have another risk factor. So do they have diabetes, family history, history of smoking, et cetera. CTs require beta blockers. It really helps us get good scans of the heart if the heart rate is slow and regular, and we do require nitroglycerin, so it makes it harder if they have an allergy to it or don't tolerate it.

Um, and calcium scores are really good tests even for people who are overweight because the signal to noise ratio for calcium is really high, so it can pull out even small amounts of calcium, whereas with the CT scan, it's much more affected by things like obesity, heart rate and artifact.

These are two images that are of a similar cut through the heart, and on this side you can see the calcium score, here on the right you can see the CT angiogram, and the big difference is pretty evident. With the calcium score, there's no contrast, so all of the softer structures like the coronaries and the ventricle, it's hard to differentiate between the lumen of the heart and the myocardium of the heart.

The things that really stand out, if you look up in the top right corner, calcified areas show up as bright white. Whereas with the CT angiogram, since we have a bunch of contrast in the ventricle, you can see the mitral valve, you can see the right coronary lit up. So the contrast is the big difference in how the scan is done, even though they're both done in CT scanners.

Let's focus a little bit more on calcium scores, specifically. The idea that people who have calcium in their vasculature have higher risk for cardiac events goes back quite a few decades. They noticed back in the 1970s that people who came in with cardiac events, if you did, overexposed chest radiographs, you saw a lot of coronary calcium, and this is a study looking at 360 patients where they used cinefluoroscopy, sort of the precursor to our modern cath labs, and they saw that the more calcium you had in your coronaries, the more likely you were to have events.

It was actually a little while before they realized that the plaque in the arteries was really related to the coronary events, but there was definitely a correlation. Follow up was with CT scanning, Dr. Agatston, Arthur Agatston uh, used CT scans, which are exquisitely sensitive for coronary calcium, and actually did scans on hundreds and then thousands of subjects looking to see what the distribution of calcium was.

And as it turned out, as you got older, whether you're a man or a woman, um, your calcium score tended to be older as their age increased. And here you can see one of the early scans. This is an area of calcification. It's white. And they counted up how much calcium you had in your coronary tree based on a couple criteria.

Number one, the density of the plaque. If it was over 130 hf units, it qualified as being dense enough to count. Somewhat of an arbitrary line in the sand. If it was less than 130, it didn't count. And it had to be over an area of one square millimeter. So it had to be big enough to count and dense enough to count.

And then they counted up all the pixels and they saw what the distribution of plaque was in men and women. Of course, Arthur Agatston, his real claim to fame was he created the South Beach Diet. I think more people probably remember him for that than they do for the calcium score. Um, this has been, looked at a number of different times, and this is a little bit of a busy slide, but if you look up in the top right, this is what a CT scan looks like in a normal person, no calcification with moderate calcification or severe calcification, and if you scan thousands of people at different age groups, so different deciles, 40s, 50s, 60s, 70s, both women and men, you can see that there is this bell shaped curve of the distribution of coronary calcium.

So the, if you take a younger group, the majority of people have very little calcium, shows up as a zero. There's a few people that have low scores. If you take your average 70 year old, the bulk of the scores are going to be in the, the several hundred range. And this is for women, for men, it's staggered a little bit more to the right, but there's this bell shaped distribution.

More importantly, if you have a distribution of coronary calcium, you can actually predict events. And this slide looks at risk factors. So zero risk factors, one, two, and three, and calcium scores, and so as you can imagine, the higher your calcium score is, the more plaque you probably have, the more plaque you have, the more likely you are to have a cardiac event, and so if you have more risk factors and more coronary calcium, you tend to fall into a higher risk group.

So this made a lot of sense. If you can't have a heart attack if you don't have coronary disease and if you have more plaque you tend to be in a higher risk group. It's not an absolute but it follows a distribution that you can then give some insight into what somebody's risk factors or what somebody's risk is based on what their calcium score is.

It's a pretty easy test to do. You basically lie in the CT scanner with your feet down toward the tube and you hold your breath for a few seconds and they scan you and you're done. Calcium scores, again, require no fasting, no IVs. It's a pretty easy test.

Once they do the scan, you can actually see the images. This is the heart and anything that lights up as white is coronary calcium. There shouldn't be anything bright white in the heart unless it's calcified, so this is somebody who has quite a bit of calcification of their arteries. And then the computer, you actually tell it what areas are what, so this is the left main, this is the left anterior descending, and then it counts up the number of pixels of calcium and then gives you a score.

And so it counts, you've got 20 in the left main, 1200 or so in the LAD, etc. And it comes up with a total score. And that score, based on what your age is and what your gender is, you can actually see where you fall in that bell shaped curve. So it makes sense that someone who has a score of 6212, probably in the 90th percentile.

Um, if you are very young, so if you're a 40 year old person and your score should be zero and your score is one, you'd also probably be in the 90th percentile. But realize that this 90th percentile doesn't have anything to do with your amount of blockage, it just has to do with your overall burden of plaque, so people get confused when they see this 90 and they think oh my gosh I've got a 90 percent blockage or I've got a 90 percent chance of a heart attack and the answer is it's not true.

It just means that if you stacked up a thousand people that are your age and gender that you would have more plaque than they do.

The question I get a lot is why don't we order calcium scores for chest pain, right? Because it'll tell you if you have calcified plaque, it's a cheap test. The problem is it misses all soft plaque. Here's a 43 year old man with risk factors, came in with chest pain. They didn't have a calcium score, but they had a CT scan for other reasons, and the area here in the left anterior descending is actually not seen, and that's because there's nothing to light up.

There's no coronary calcium. Their angiogram actually showed a 90 percent blockage, all soft plaque, which ended up getting stented, but a calcium score would miss plaque in somebody unless it had calcified plaque, and it doesn't tell you the degree of stenosis. So again, not a good test for chest pain.

So imagine a patient, 65 year old woman, she has hypertension, she has obesity, she has hyperlipidemia, and you know, this is somebody you'd think they would probably benefit from being on a statin, but she researched them and declined. And so we got a calcium score and it turned out to be moderately high, but it did put her in the 90th percentile based on her age.

And that really, for a lot of people, frames it in a different way. It's no longer I have risk factors for coronary disease, they have coronary disease. In the strictest sense, they've got plaque in their arteries, they've got coronary atherosclerosis, they've got coronary disease, however you want to put it. But this framed it a little differently and she was happier to be on statins just because, there is a really good reason for it.

Reclassification is something that it's very, very helpful. So here, this is a busy slide, but this is from a paper looking at primary prevention in atherosclerotic cardiovascular disease risk. And you know, it's, it's easy when they're low risk. If you get your average 20 year old that comes in with no risk factors, you wouldn't necessarily think you need to treat them.

Likewise, if you have somebody who's already had a heart attack or bypass surgery, they're very high risk. And everybody thinks it's a good idea to be treated. If you're in the middle, sometimes it's a little bit different. You may have family history, you may have high cholesterol, which doesn't always translate to coronary disease, but a lot of times it does.

And so you need something to help give you a push in one direction or another. So they recommend risk discussion, consider statins, but if the risk decision is uncertain, they actually say consider measuring a coronary calcium score in selected adults. And for a lot of people, I think this is very helpful in reclassifying the risk, either higher or lower.

So, it's also important if you've got a score of zero. So, people always ask me, do you ever see calcium scores of zero? And the answer is we see a lot of people with heart disease. But yeah, we do see people whose scores are zero. Here's an example of a woman aged 70. And she wasn't sure if she wanted to continue on statins, and I said, well, you know, let's take a look.

If you've got a calcium score that shows plaque, you know, it's a really good idea. If it's zero at age 70, then it's pretty unlikely that you've been making plaque, at least for the last few years. It hasn't had a chance to calcify, and her score was zero. And, uh, you know, she can make an informed decision. But there are people that on both sides, it's helpful to reclassify them because you can take your average diabetic, hypertensive with hyperlipidemia and if their calcium score is positive, they're in a higher risk group than if their calcium score is negative.

It's also very helpful in compliance. So there's at least a couple of papers showing that if you have somebody who's at risk for cardiovascular disease and you get a calcium score and it's positive, they are much more likely to take their statins and do other modifying factors, whether it's stopping smoking, losing weight, etc., if they know that it's not just theoretical, it's actual. They have heart disease and so it becomes much more important for them to comply.

The other question we get a lot about is when do you repeat your calcium score? And the short answer is, if it's positive, never. And it's especially true if the score is high. So the calcified plaque is always there. It doesn't go away. Even with medications, um, and so your score, if your first score is one, if you scan again in a year or two years, it's going to be higher than one.

It's going to be 10 or 100. If you wait several years, it's going to be much higher, but seeing that score go up doesn't really give us as cardiologists any additional information on how to treat it. You kind of think about it as a binary thing. If you've got heart disease, you should be treated for heart disease.

So, knowing that you have the process, you should feel comfortable being aggressive treating, and then watching that number go up doesn't really add to things. Plus, you don't really need the extra radiation. Here's an example of somebody who came in time zero, their score was over 2000. And then several years later, it was 2700.

But again, they were high risk to begin with. They're high risk and, you know, it's several years later and it doesn't change the equation. The one caveat is if your score is zero, so you may have a score of zero and you're in a low risk group, but you're still have risk factors, repeat scanning in about five years, if it's zero again, is a very good negative predictor for events, and sometimes you actually catch people who went from zero to higher than zero.

Here we see a calcium score of a 54 year old man who had a prior negative calcium score at age 47 with some risk factors, decided to repeat it to see if there had been any changes. And as you can see, there's no plaque in the left system originally, but eight years later, had a little area of calcium. Score didn't jump a lot, went from 0 to 1, and it still didn't put him in a high risk group, but the differences from 8 years ago, this was a very theoretical, I have risk factors for coronary disease, and now it's an actual I'm making plaque, helped sort of reframe the idea, and at least in his mind, wanted to change some things, got on cholesterol medicine, changed some behaviors, so very helpful in repeating it. Now once it's positive, again, the process is in place, you don't ever need to repeat it again.

There are a couple of problems with scores of zero that can happen. So sometimes it's a computer issue. This is actually someone whose score was 0.46, but due to the computer rounding down, it actually got rounded to zero. So the, the total Agatston score was really 0.4, um, rounded from 0.46 to zero, and so it had to be replaced.

So you can still have plaque, you can see the plaque, but it can be a simple rounding error.

You also have to be careful about the density of the plaque. You can have plaque in the arteries here. You can see plaque in the proximal LAD, but as you recall, the study originally only evaluated, or only counted plaque that was greater than 130 Hounsfield units. So if you have plaque that is less than that, so this could be 129, 120, 90, it's still plaque, it's still visible, but it doesn't count towards your total score.

You can look at it two ways. Number one, it still kind of puts you in a low risk group depending on your age, but if you have the process, you may want to think about being aggressive as far as treating it, and so we usually put in verbiage that shows or says, although the patient score was technically zero, plaque was seen, which was not dense enough to count towards the total, it should be considered an abnormal calcium scan.

And again, you can make some decisions about behaviors and treatment, etc.

So there's some frequently asked questions that I get. Um, here's a good one. If my patient has a positive calcium score, do they need to see cardiology? Um, here's a 70 year old asymptomatic patient, recent calcium score. They're taking red yeast rice, which in some cases may work to help lower cholesterol. In some cases, there's no active ingredients, um, over the counter omega 3s, which again, not a lot of data in helping with high LDL. Um, and their LDL is 124 and their calcium score was 127. Put them in the mid range, 50 to 75th percentile for their age. Um, and you can look at it two ways. I think that it's, it's pretty reasonable if you feel comfortable treating high LDL, you put them on a statin, you put them on a baby aspirin, you modify blood pressure, talk about better diet, exercise, etc.

Um, but a lot of people feel more comfortable if they have somebody that they can talk to about their coronary disease, which technically they have. And from a practical matter, let's say, even though very few people actually go on to have events, if you have known plaque in your arteries and you want to have somebody that you can call if you do have problems, seeing a cardiologist is very reasonable.

These people, in the strictest sense, do have heart disease and it's a very reasonable ask as a person with heart disease to see a cardiologist. So is it mandatory? Yes. Um, or sorry, is it mandatory? No. But is it a reasonable idea? Yes. So that's it for calcium scoring. Again, calcium scoring is a very cheap, uh, very safe, low dose radiation test for screening asymptomatic individuals. It is not in, not a good test for people who are having chest pain, um, and we talked about some of the details.

So CT coronary angiography is, is similar in that it's done in a CT scanner. The biggest difference is that you get contrast and that allows you to evaluate for soft plaque, not just hardened plaque. And it really allows you to make a determination about not only do you have plaque, yes or no, but how severe is it? This is not a new concept. This is a Time magazine from 2005, and it seems like, you know, we are talking about the same things even 20 years later. We're talking about how to stop heart attacks, CT scans, cyber spies, et cetera, et cetera. Um, but even back then they were looking at people who were at risk for having heart disease and getting some insight into patient's coronary anatomy, even before they ended up in the hospital. The reason we haven't done CT coronaries for many, many years is because the heart, as you know, is always beating.

We want it to beat every second of every minute of every day, but it makes it kind of hard to image unless you have very fast CT scanners. This is what a non gated CT looks like. So if you used to get a chest CT, the heart is just a big blur. And even though you can kind of get a sense where the coronaries are, you really can't make heads or tails of whether or not there's plaque in it or stenosis or anything like that.

And so it was kind of ignored up until we started, the heart was ignored on CT scans up until we started getting very, very fast, um, initially EBCT, and then spiral slice CT. So what it does is it takes scans through the heart, usually in diastole. You can take it in systole too, but the heart is most still in diastole.

And it takes each of these individual areas, focuses on the different parts of the coronary anatomy, and then stitches them together into what's called a curved reformat, which is really, it's not truly an angiogram. These are not contiguous slices, but it looks like one. And you can actually spin these around and look at them and make an evaluation of the coronary anatomy.

Here's an example of a 74 year old. This is somebody who was in the hospital, very sick, had a Whipple procedure, no history of coronary disease, but started having chest pain. And they were sick enough that they really didn't want to do a heart catheterization. So they said, well, let's get a CT instead.

And sure enough, he had pretty severe blockages. You can actually take a look here in the prox LAD and mid LAD. And this is a severe stenosis, um, in the proximal LAD. And this is what a 3D view of it looks like, and this is what the angiogram looks like, and you can pretty clearly see that severe narrowing.

So this is before the stent, this is after the stent, and they did much better after getting their arteries taken care of. This is what a CT scan of most of our patients who come through look like. This is a 53 year old woman with chest pain and risk factors for coronary disease. And their arteries are clean as a whistle.

So there's the LAD, there's the diagonal branch, circumflex OM, and the right coronary. And there's continuous contrast throughout, there's no soft plaque, there's no hard plaque. And, you know, even though the, it's really nice to be able to see blockages, um, if someone's pretty sick, we, we usually take them to the cath lab.

If someone is, um, moderately ill, you can make a decision. But if, if you really want to try and prevent needing to go for an invasive test, there's a lot of people where they're, they're sick enough or they have symptoms that are strong enough that you're thinking about a heart cath and you can do it in another way and avoid any vascular punctures, some of the complications and cost and time.

And so for a lot of people with stable symptoms, it's a very reasonable test and we're gonna talk about that a little bit, a little bit later. Um, when you look at CT coronary angiography to evaluate for stenosis, that's an actual blockage in the heart artery, usually greater than 50 to 70 percent, the stress tests have been the gold standard for years, but they're not that great.

And depending on the population that you're looking at, you can see that SPECT, which is nuclear stress testing, is usually in the kind of 80 percent range. Now it's, it's worse in people where there's a lower prevalence of the disease and the specificity is higher when they're, they're less prevalent.

But the same thing goes for CT, but you'll notice that CT scanning is usually pretty high. So sensitivity really refers to this is a person that has the disease. So they have plaque, they have a narrowing, and the test was able to detect it. So pretty high numbers overall. You'll see lower numbers of sensitivity in low risk populations.

Specificities where, hey, I see that, you know, you're having chest pain, but you don't have disease, where the CT is really able to discriminate and say, you do not have plaque. And in lower risk populations, it really shines. In higher risk populations, the specificity is a little bit lower. But overall, as far as the pooled results, you get a much better sensitivity and specificity with CT than you do for nuclear stress testing.

And that goes for stress echo as well. So on a good day, sensitivity and specificity for most stress tests is in the kind of 80 to 85 percent range. For CT, it's usually in the kind of mid 90s to 100s if you're talking about ruling out disease in low risk populations.

So a couple of studies we want to look at. Here's a 10 year follow up after coronary computed tomography angiography in people who have suspected disease. So about 2,000 patients with suspected but never diagnosed and they all got CT scans and then they followed them and when they found was that the event rate, meaning did they have a heart attack, did they need a heart cath, did they end up in the hospital for cardiac issues, was really pretty low if you had a normal CT.

Um, when they found coronary disease, much like you'd expect, the event rate was higher. Still not very high, but higher. And what they could do is they were able to reclassify people, much like with the calcium score. If you're not sure if you're low or high risk, the calcium score can give you some insight.

Same thing with CT coronary angiography for the patients who have symptoms and risk factors for coronary disease. This is a really nice trial as far as prediction of five year events in people with stable chest pain. So again, you're not going to take people who are having unstable symptoms, having a heart attack, acute MI, and go to the CT scanner for the most part. You're going to go to the cath lab. But if you've got stable ischemic heart disease, having some chest pain could be angina, likely or unlikely, and you scan them. That's really the sweet spot for CT coronary. So this is about 4,000 patients who had been referred to the cardiology clinic for evaluation of chest pain.

So they didn't think they necessarily needed a heart cath, but they were going to evaluate them either from um CT scan or do their standard care, which was maybe a stress test, maybe not. And what you saw was a couple of interesting things. The, the rates for invasive angiography were higher in the CT group than in the standard care group for the first few months, but overall rates were similar.

So when you see plaque in somebody's artery and they're having chest pain, there's this instinct to say, well, you got to go to the cath lab. Um, we're learning more that you really don't for most patients, and you're not going to necessarily prevent a death by going to the cath lab in stable patients.

Um, but at least in this trial, they saw, uh, an increased risk of cath. What was very interesting though, is because you can actually see the plaque, more preventative therapies, and think statin, were initiated in patients with the CT group. So when they, they did the five year evaluation, CTs actually in the standard care, CTs compared to the standard care group afforded a lower rate of death from coronary heart disease or nonfatal MI.

Everybody initially said, well, that's great. That means people are getting more caths because you're doing CTs and it must be that you got stents and that's saving your life. And the answer is absolutely not. Stents in stable ischemic coronary disease may make you feel better and it's definitely better than just medications in some people, but it doesn't prevent future heart attacks.

And so most, and we know this from the COURAGE trial and the ISCHEMIA trial, that you're not dying for lack of a stent even with, you know, having chest pain. But what you are doing is you're seeing inside the wall of the artery and as opposed to a stress test where you really don't have any insight into what's going on in the plumbing, with a CT you can actually say, hey, you know, you may not need aheart cath, but you've got plaque in your arteries, and so we're going to start you on aggressive therapy.

Statins, aspirin, blood pressure, you know, diabetes control, all that stuff. Whereas with a stress test, the only question we're answering is, are you or are you not high risk? And do you need a heart cath? Your freedom from events is really what you're looking for. If you have a negative CT, does that mean you've got a quote guarantee or not?

And nothing's guaranteed, but this is a study that we did a few years ago, and it's, it's actually been reproduced for longer periods of time. But if, if you were one of the subset of people that came in with chest pain and had a completely normal study, no plaque whatsoever, like that example I showed you, your rates of events was essentially zero.

And it makes sense. If you don't have any coronary disease, you really can't have a heart attack. You got to have some plaque. So, and this, this bore out several other studies, five years, seven years. So, if you have a completely normal study, you're probably good for at least a little while.

This has been incorporated into the chest pain guidelines. This is from 2021. And so this was the first time that the guidelines included pretty strong language for the use of CT coronary angiography in different groups with chest pain. So pulling some of the tables, this is intermediate risk patients with acute chest pain and no known coronary disease, and it gave it a 1A rating.

That's a pretty good rating for anatomic testing with CT coronary angiography. Um, even with mildly abnormal stress tests, they, they said you can actually, it's reasonable to use CT versus going to the cath lab, um, with a lower recommendation, but still a reasonable thought. Um, even in patients who have acute chest pain and they've had prior bypass, um, it gave a recommendation of one, even though the supporting data wasn't as strong, but you can actually use CT to evaluate people for patency of vein graft.

So it rose to a higher level of indication in the most recent chest pain guidelines, and we're seeing a lot of people now leaning more towards CT than stress testing for chest pain. This article from the New England Journal came out in 2022, and this was CT or invasive coronary angiography for stable chest pain, and this was interesting because it was people who were at least 30 years of age referred for cath in 26 centers in 13 European countries.

So these are people who under normal circumstances they would go to the cath lab, and instead they randomized half the group, to go to the CT scanner. Um, they were ineligible if they were on dialysis. So if they had bad kidneys, if they weren't in sinus rhythm, and that's one of the Achilles heels of CT, you can't be in AFib.

And then they assigned half the group for CT and half the group for invasive. Um, and then they followed them for three and a half years. And the interesting thing was that only about 22 percent of the patients in the CT group ended up with a cath. So everybody in the cath group got a cath, but only a fifth of the patients got a cath in the CT group.

A lot of people who have chest pain don't have a cardiac cause, and we see this in our own cath lab. All comers, it's only about 60 percent of people who end up either needing stents or surgery, and about 40 percent of people end up, hey, you know, your arteries are clean, and that's great. We think doing a heart cath for good reasons is great, but if you don't need to have an arterial puncture, if you don't need to have the time and expense of going to the cath lab, and you can find out that you're, you don't need that invasive test up front, there, there, for a lot of people, that's an advantageous way of evaluating you.

The other interesting thing was, is that even in people who were found to have plaque, there's really no difference in quality of life and no difference in, um, in death rates. And this is based on comparison to the COURAGE and ISCHEMIA trial. So, you know, people are not dying from lack of having a heart cath. Putting in stents absolutely can make a lot of people feel better, but in stable ischemic coronary disease, that means you're not having an actual heart attack; there is no life saving benefit in receiving a stent.

A little bit about appropriate use. So, these have been incorporated into the 2023 guidelines. And I've pulled out four of the tables because I think these are the groups that we see most often and have questions about. Number one, this is a group with no symptoms. So they're not having chest pain. They have no known, um, atherosclerotic cardiovascular disease.

And depending on whether you think they're really low risk or really high risk, you can decide what test to do. I will say that the very low risk group, if you take your average 20 year old, who's got no risk factors, they really recommend, and so do I, no testing whatsoever. You know, they're asymptomatic with no risk factors.

Why are we going and exploring for coronary disease? But for the bulk of people who have risk factors and just want to know, they actually think that calcium scoring is a really good idea, a much better idea than doing stress tests, where you can't actually get a sense for number one, do they have plaque?

And more importantly, since there's up to a 20 percent false positive rate, if you have an asymptomatic person and then they come back with a false positive stress test, they're usually going to end up with more testing. Obviously, if they're very, very high risk, you know, it's a little bit less likely that it's going to be beneficial to do screening.

Um, but still, it's not an unreasonable thing. If you already know they're high risk, you probably should be treating to begin with.

What about asymptomatic patients with prior revascularization or MI? So, this is somebody who you had your heart attack five years ago, you feel fine. Or you had your bypass surgery and you feel fine. So, this is a little bit of a different question. You're not screening anymore. These are people who are a known quantity, so the screening test calcium score is a terrible idea.

Someone has had bypass surgery, you don't need a calcium score to tell you that they have coronary disease and should be aggressively treated. Likewise, it's not unreasonable to do things like stress tests, but they don't recommend it. Um, the bulk of people who have no symptoms should probably fall into the no test group in general.

Um, there are some subsets where if they're high risk for silent ischemia, um, doing some sort of provocative test makes some sense. But again, the big take home is that if they're asymptomatic, you don't want to screen them if you know they have coronary disease and it's probably better to just leave them alone.

What about symptomatic patients? So these are patients who are coming in and they're having chest pain that could be angina, but you don't know anything about them. They've had no prior testing and they don't have any known coronary disease. So again, with symptoms, they do not really recommend calcium scoring, which we talked about.

You can miss a lot of soft plaque by doing a screening test in a symptomatic patient. It's still not unreasonable to do tried and true stress tests. Um, but they actually raised CT coronary up to, on sort of equal par with stress testing as far as evaluating symptomatic patients to see do they or don't they need to goto the cath lab.

It's also not unreasonable if they're pretty high risk and they're having angina to just jump right to the cath lab. Again, sometimes we guess wrong, but you know, sometimes you have to think, okay, what's going to keep them out of the emergency room? Or if we do this test, are we done with the evaluation?

And the problem we sometimes have with stress testing is they're having chest pain. They've got risk factors. You do a stress echo. And then a week later, even though the stress test was negative, they're having more chest pain. They're either going to the ER, they're getting a cath, or you're doing another test.

In some cases, it's probably better to pick the test that's going to be one and done, and then you've got your answer. Symptomatic patients with prior MI, uh, this is a little bit easier. So if you had a heart attack five, ten years ago, and you're having your heart attack pain, most of us will say, hey, you probably just need to go to the cath lab.

Um, if you really think that they're non anginal symptoms, you probably don't need to do much of anything. But again, If you know that they've had prior revascularization, they're not a screening patient.

Thinking about this, I, you know, there's not really great flow diagrams. There are some, but they're kind of complicated. I was thinking to myself, well, what do I do? So the question is coronary disease. The first question I always ask is, do you have symptoms? And if they have no symptoms, then, you know, they're doing okay.

Well, they've got lots of risk factors. I say, well, we probably should treat you statin, you know, depending on whether we know more about them, aspirin, blood pressure control, diabetes, knock the cigarettes out of their hand, watch their diet, exercise, et cetera. Well, a lot of people say, well, I just don't want a statin.

So I use calcium scores a lot for the reason we talked about to say, okay, well, you've got risk factors, but I want to know, do you actually have the process? And then if their calcium score is zero, we have a conversation, well, you still got risk factors. Do you want to treat or do you want to wait a little bit?

If they've really got a positive calcium score, there's no quibbling about whether or not they have coronary disease and it's still up to them if they want to be aggressive or not. I usually lean towards, hey, do you want to wait until there's a problem or do you want to be aggressive upfront?

What if they're having angina? So if they're really having angina, they come in and it's like an elephant sitting on their chest when they walk down the block, I don't have any problem saying let's go to the cath lab because we don't want to miss something. But if you're not sure, or if they really don't have angina, if every time you push on their chest it hurts, I'm like, well you don't need a heart cath for that.

But sometimes we're in the middle and I really need to know what the next step is, so we'll do CTs that were on the next page. And if the CT shows no plaque, we're done. Free of plaque means they're very unlikely to have an event. Um, manage the risk factors if you need to, but you may want to look for other causes for your chest pain.

If they do have plaque, but it's not flow limiting, we treat them usually with the statin or other medications. Um, and if they have flow limiting plaque, then they go to the cath lab.

Some frequently asked questions that I get, um, number one, why don't we get a calcium score when we get a CT coronary angiogram? And it's, it's a logical question. They're in the scanner at the time. One has contrast, one doesn't. So why not get a calcium score and then afterwards just scan them again with contrast?

There's a really good reason. So these are two different tests with two different indications and the results can be very confusing. So here's a good example from years ago. We actually published this years ago when we started doing CTs. We had a calcium score on this 35 year old man with risk factors.

And he was having chest pain and his calcium score was zero, but when you did the CT angiogram, he had pretty horrible looking disease. So his LAD was essentially occluded or subtotally occluded. Here's the cath. You can see how it looks on CT. And the reason it doesn't show up on the calcium score is again, it only sees hardened plaque.

So all the soft plaque that you see here is invisible to a calcium score. It's very visible to the CT coronary angiogram. So you can have a patient who comes in with chest pain and the calcium score is zero and the report from the calcium score says, hey, your score is zero, you're low risk. But the CT coronary says, you've got a nearly complete blockage, you're high risk, you need a heart cath.

Calcium score did you no good. The other example is, well, there are some places where they scan you and if your calcium score is really high, they say you're high risk. And then they do the CT angiogram based on that. The problem is, is that if you have a high risk calcium score, you can still have open arteries.

There's a lot of people that have calcification in the media of the artery and their arteries are wide open. And so if you're having symptoms and you get a calcium score of a thousand, it puts you on edge. The, the CT scan does have a little bit of an issue seeing through really dense calcium, but I've scanned people with,1,00- 2,000 and you can see in a reasonable amount of patients.

So high calcium score or high calcium in the arteries makes CT harder, but if they're not having symptoms, no matter what you find, it's really not actionable. So high calcium score, we treat you aggressively, but if you have a high calcium score and you feel fine, you probably don't need to do further testing, you don't need to do additional stress testing, especially if they already exercise at a good clip, and you certainly don't need to jump to the cath lab.

I've cathed a lot of people with high calcium scores and a lot of them have open arteries and especially if they're asymptomatic. So this is the other side of the question. So why don't we just screen with CT coronary since it does see both soft and hard plaque and this is the example that sort of is not the rule, but there's always these outliers.

This is a very young man that came in with strong family history of premature heart attack. Everybody in the family died of a heart attack before age 40. And you know, his calcium score at age 34 would probably be zero no matter what. And I can tell you, it is because he's got plaque, but it has not had time to harden.

CT coronary angiogram, will see all this soft plaque, and it's not, it's not going to cause symptoms. It's a, you know, mild amount of plaque, but if it ruptures, it can absolutely cause a heart attack. So if you've got a strong family history, you could actually make a case for saying okay, just treat you aggressively.

This is an individual that really wanted to know how far behind the eight ball he was and, you know, putting it in the context of, hey, we see a soft plaque not causing any problems, um, for him, he got very aggressive with his lipid management and exercise, et cetera. But again, there's a good reason that we don't do CT coronaries in the majority of people.

Number one is radiation dose. So a calcium score, as we talked about, it's pretty low level of radiation, again, one to three millisieverts. CT coronaries can be, depending on your body habitus, very high, um, and you don't want to give somebody radiation that they don't need. The other thing is the cost, 80 dollars versus several thousand.

Um, here's an example of someone who got a CT coronary at age 70, um, and they had risk factors, no symptoms, and again, you can see the calcified plaque here, the soft plaque here, they got a fair amount of radiation, 21 millisieverts, and I would suggest to you that if a calcium score had been done, it would have absolutely picked up the hardened plaque, would not have seen the soft plaque, but knowing that you have soft plaque there doesn't change what your management is, you're still going to treat aggressively either way.

So probably didn't need the extra radiation, contrast, money, etc.

Okay, so we've talked about a lot of things, but back to the summary slide. Two different tests, both done in CT scanners. The calcium score is for asymptomatic patients with no history of coronary disease, low radiation dose, no contrast or IVs, no fasting. It's inexpensive. And again, if you see plaque, you're done.

You want to treat them aggressively, but you really don't need to do additional tests. They're asymptomatic going into the scan. They're asymptomatic coming out of the scan. Leave them alone. Generally, the sweet spot is 45 to 75 for men, 50 to 80 for women. Now, caveat to that, there are some people who are really, really high risk family history or, um, risk factors that are non-standard. And there are some people who are younger than 45, the calcium scores, and some of them are positive, but this is generally the, the group that you wanna look for. Um, and it's a pretty good test regardless of how big you are, what your heart rate is, because the calcium stands out so well. There's a high signal to noise ratio, so it's affected by, um, obesity and heart rate.

CT coronary, again, indicated for chest pain. Think of it as a non-invasive heart catheterization. You do get more radiation, but in somebody who's got chest pain and you need to know the answer, it's not an unreasonable thing to do, even with a moderate dose of radiation.

You do get contrast, and you're obligated to around 80 to 120 cc of contrast, so if you've got bad kidneys, it may not be the ideal test for you. Um, heart caths, we can get by with less than 50 almost every time, but in general, most, most people don't have any issues when getting this amount of contrast.

It is paid for by most insurance for the right indications, and then again, if there's plaque, you can make decision for do they need a heart cath if they've got severe disease or do they just need it a statin, or you know, hey, maybe they've got normal coronaries and they don't need anything. It does usually require some additional medications.

We usually like to give beta blockers. I give them as an outpatient, usually 50 milligrams of Toprol for five days or four days prior to and the day of the scan. We like to give nitroglycerin because it makes the arteries a little bit bigger on the scan. And this test really is affected by heart rate and obesity and movement artifacts.

So if your heart is irregular, if you're in atrial fibrillation, it's not a good test for you. If your BMI is big and there's no absolute cutoff, sometimes it's, it's what your shape is. But BMI's over 40 get problematic.

So we've talked to you a lot about how primary care, you know, and I think primary care, whether you're family practice, internal medicine, obstetrics, general cardiology, how they would use this type of test. But we're using it sort of on the front end of planning for, uh, angioplasty. So some of these patients that end up getting CT scans for chest pain, we think they do need a heart catheterization.

And there was just a recent journal in JSKI, which is our Society for Cardiovascular Angiography and Interventions, where they had a special issue on The Role of Cardiac Computed Tomography Angiography in Cardiovascular Risk Stratification and really as it pertains to interventional doctors. We actually published one of the lead articles in it and this is sort of a comprehensive review and as opposed to the primary care version, this is really how do we use this in the cath lab.

And we actually can take those images and plan for our procedures. We can say, Hey, not only do I think you need a heart cath, but I think you're going to need this long of a stent. We think that we're going to have difficulty in these areas because of the type of plaque that you have. We think we're going to have to use these tools and you can get a lot of insight into what your procedure is going to be like, even before they ever get to the cath lab.

Um, here's an example of somebody who has very complex coronary anatomy, they've had multiple bypasses that you can see that are patent, so CT can tell you that you've, what your, what your bypass situation is even if you don't have an op node. And if you're interested in this, you can certainly look it up at JSCI.