Dr. Nero discusses with ways to evaluate coronary artery disease with Dr. Cheerag Shirodaria from Oxford. Dr. Shirodaria and his team at Caristo Diagnostics have developed a ground breaking technology that allows us to evaluate not just the severity of a coronary artery lesion, but also how inflamed it is and how likely it is to cause a heart attack in the future. We also briefly discuss the role of CT coronary calcium scoring, CT angiography and stress testing.
Evaluation of Coronary Artery Disease and Coronary Inflamation
Dr. Thomas Nero: Good morning. I'm Dr. Thomas Nero and welcome to Future Pulse. Today I have the pleasure of talking with Dr. Cheerag Shirodaria. Dr. Shirodaria is the CEO and co-founder of Christo diagnostics and an honorary consultant cardiologist at Oxford university. Today, we're going to be talking about the technology that he and his partners have developed on evaluation of CT angiography and where that stands in our diagnostic armamentarium.
Good morning, Dr. Shirodaria. We know that there's a lot of ways to evaluate coronary artery. We commonly use stress testing and we are increasingly using CT coronary calcium scoring and CT coronary angiography for this evaluation. Where do you see those tests being useful? And where do you see imaging going in the future as far as our ability to help diagnose coronary artery disease?
Cheerag: It's a pleasure to be speaking with you today, Tom. Part of the problem that we have in the way that we currently manage our patients is. All of our tests to focus on identifying narrowing in the coronary arteries or the consequences of narrowings, which we call ischemia.
We have a variety of ways that we do that either with stress testing, with myocardial perfusion imaging, with MRI, with stress echocardiograms. But the problem we have is that over 50% of heart attacks occur in people who don't have major narrowings in their coronary arteries and who don't have ischemia.
And for those patients at the moment we’re perhaps falsely reassuring that everything's okay. When perhaps things aren’t. And that's because we've never had a way of working out what the risk is in those patients. Now the disease process, at least to heart attacks is called atherosclerosis. And we've known for over 50 years that's the risk for atherosclerosis, which leads to narrowings in the coronary arteries, build up a fatty plaques. We've know that atherosclerosis is an inflammatory disease, but we've never had a way of straightforwardly measuring inflammation in the actual coronary arteries for many of our patients.
Now the technology that we developed at Cresto allows us for the first time to take a routine coronary CT angiogram, which is now becoming the first line test in all the international guidelines for the assessment of people with stable chest pain, we can take that standard image and measure how inflamed the coronary arteries are, but also the risk associated with that level of implement of that individual patient having a heart attack, fatal or nonfatal. And that's really where we believe that our technology can be game-changing both for patients and for physicians because we allow them for the first time to measure and quantify the amount of inflammation in the coronary arteries and the risk associated with that.
Tom: We often will use CT coronary calcium scoring because it's relatively quick, relatively easy way to assess. But it seems like we're missing something with this technology that what we're looking at is the calcium, but we're actually not looking at the biologically active portion of the plaque.
Can you go through when you would use one of these technologies versus another?
Cheerag: Coronary calcium score is a very good first line test for looking at. The problem with calcium scoring is calcification. And the appearance of calcium occurs quite late in the disease process. And in some ways, once a narrowing is calcified, it's less biologically active.
So in other words, less likely to cause risk of a heart attack. The second problem we have is that if we have a patient with increased coronary calcium, who we think perhaps we need to start medical treatments such as statins. We know that many of those treatments actually increase the coronary calcium.
So it no longer becomes a useful way to monitor a patient's responsiveness to treatments because what we're imaging is inflammation. It's at an earlier stage of the disease process before you often have the coronary calcification, but even if you have narrowings in the coronary artery, we can tell which ones are inflamed and which ones are not.
We're giving, as you rightly pointed out, biologically relevant information. So if I was to take a hundred patients coming through coronary CT angiogram departments, about 40 of those 100 patients would be normal or pretty near normal by conventional analysis. And at the moment we as physicians are, are reassuring those patients that everything looks okay.
There were no narrowings there. The arteries look pretty clean. You've got a clean bill of health. What we've actually shown is that if you were to take that group of near normal patients, about 20% of those patients actually have significantly increased coronary inflammation that actually increase their risk of having a fatal heart attack by at least two to three fold.
And we can modify that risk straightforwardly, like giving treatments, such as statins, but also aggressive lifestyle treatments to those patients. So basically giving advice to them that can alter their ultimate problem.
Tom: This is absolutely fascinating, wonderful, technology. Certainly we’ve always known that when we're doing stress testing, what we're stressing is whether there is or is not a lesion present at that time, but not necessarily what's going to happen in the future.
The technology that you seem to be developing really is looking at that future risk and giving us ways to modify it. Do you see that this technology can also be used to see about the efficacy of what we're doing and are there times when you're seeing, even though we're giving the correct therapies as far as our guidelines, that somehow we're missing the boat.
Cheerag: One of the problems that we currently have is that when we prescribe treatments to our patients, we don't really have many good ways of measuring whether those treatments are having an effect on modifying an individual patient. So we can measure a patient's cholesterol. We can measure a patient's blood pressure, but beyond that, we don't really have any way of determining whether a specific treatment is modifying risk.
Now, the very important groundbreaking nature of our technology is that we can modify and monitor treatment responsiveness because what we measure is biologically active. And we can measure these changes in inflammation from a CT scan. So for instance, this technology is being used in Europe now, and we have patients for example, who have had a cardiac CT, we performed an analysis at CARISTO where we've identified the patient is having increased colony inflammation, treatments have been started.
And the patients come back 12 to 18 months later and has had a repeat scan. And we've been able to see whether those treatments have had any effect on reducing inflammation and modifying risk. And indeed, in some cases we've seen dramatic results where inflammation has been almost wiped out with treatments, but equally we've seen cases where quite aggressive treatments have had very little effect on modifying risk.
And this fits with what we see in clinical setting. We still see patients coming back with heart attacks, despite us giving them the cocktail of drugs. And this gives us a way of identifying these patients who perhaps aren't responding to treatments, but equally reassuring patients who actually are responding to treatments.
Tom: Well, this also be able to help us in identifying patients who can use non-pharmacologic measures like diet and exercise and improving their outcomes and improving their scores.
Cheerag: Absolutely. Because fundamentally what we are measuring is disease activity. Any measure that you take to modify that disease activity.
And that could be both pharmacological drug treatments, but it can also be changes in lifestyle. We can ultimately measure the change in disease activity as a result of, of whatever intervention has taken place.
Tom: Well, this has been a wonderful discussion, Dr. Sheridari, I thank you so much for taking your time today to help us understand not just your technology, but also where it fits in with our other techniques for identifying coronary disease.
Have a great afternoon
Cheerag: and you too. Thanks very much. Bye bye.