Scanning your heart
What's the best way to look inside your heart? Chris Smith tracked down Michelle Williams, a member of the team at Edinburgh University that have just won the British Medical Journal “imaging team of the year” award for their work on a project called the Scot-Heart study, which could cut heart attacks deaths by half in certain groups of patients....
Michelle - We’ve been doing CT scans - that’s a non-invasive type of scan where you go into a doughnut shaped scanner, lie on your back, and we inject some contrast, some dye, to light up the blood vessels around the heart in order to look for any narrowings or any plaque in those blood vessels that might be causing symptoms of heart disease, or put people at risk of having a heart attack in the future.
We recruited 4,000 people throughout Scotland. Half had CT scans and half didn’t and we followed them up to see what happened to them. We showed that the group that had the CT scans, and the results of the changes in treatment based on the information from those CT scans, had half as many heart attacks or death due to heart attacks than the other group. So that’s a really big difference between the two groups of people.
Chris - Yes indeed; you can be very proud. What were these CT scans showing you that enabled the cardiologist to then make changes to the way those patients were handled to get that dramatic reduction in heart attack risk.
Michelle - CT scans showing us narrowings in the blood vessels and the heart. Previously, in order to identify these things we had to do a test involving a wire being put into a blood vessel in the wrist, fed in towards the heart, and then dye injected around the heart, whereas a CT scan doesn’t involve any of that. There’s a small drip, a venflon, in the arm and then we can use that to put some dye and get the CT pictures, which are kind of like X ray pictures in a 3 dimensional way so that we can see all of the heart and all of the blood vessels.
The Scott heart study looked at narrowings in the blood vessels and what that told us about what happened later on to the patients. But we’re now realising we can actually get more information from the CT scan rather than just about the narrowings because the CT can show the plaque itself that’s causing the narrowings. There’s different types of plaque and some are more high risk and, potentially, people with these high risk plaques might need different treatment or better treatment. That’s what we’re going on to look at next to see if we can identify the highest risk people to make sure they get the best treatment.
Chris - How do the plaques differ?
Michelle - CT scans use X rays and that tells us about the density of the material. We can use that to identify very dense areas that might have calcium in it, or very low density areas that might have fat, or dead cells, or lots of inflammation in them. That can tell us a bit more about what’s going on in the wall of the blood vessel rather than just what narrowing it’s causing.
Chris - Now you’re beginning to ask if we look at enough people, and we’ve got enough of these different types of plaques, we can see which ones are likely to be the high risk ones, which are the lower risk ones, and that gives us even more information about who we need to treat?
Michelle - Yeah, that’s exactly right. That’s our current theory and that’s what we’re going to be working on next so I’ve very excited about finding out what that shows.
Chris - is this cost effective though, Michelle, because that’s a big group of people to be scanning? So what fraction of them might you be able to save from having a heart attack at all and, therefore, what’s the cost of scanning that huge number of people?
Michelle - The beauty of the CT scan is that all of the tests that we do to look at the heart, it’s one of the cheapest. So if it can give us lots of information then that’s a really good one to go for rather than the more expensive, fancier tests. It’s also one with very few side effects - it’s a low radiation dose test. Many people can have it particularly if they can’t go into other different types of scanners for a variety of reasons. In our study we showed that we halve the rates of having a heart attack, or dying from having a heart attack and that really is a big difference so we'll see this increasingly coming into more and more guidelines. The number of CT scans we’re going to do is going to go up and we are going to need more CT scans, more people to look at the CT scans, and more people that can do the CT scans, and that’s going to be a challenge. But it’s not going to be an impossible one because it is going to make a big difference.
Chris - What’s been the reception to your findings and you getting this award? Aee people embracing this - are they going for it, not just in the UK, but internationally: Australia, US, and so on?
Michelle - The reception’s been absolutely fantastic. In the UK it’s already changed national guidelines. In the rest of the world they’re very excited about it as well, particularly in America. At the same time as we did our study there was an American study called “Promise” that was going on at the same time, and the combination of these two studies have shown us really interesting and important things about this population. So around the world it’s been the recipient of quite a number of awards so far and it’s only just getting started I think.