Marc Dweck, University of Edinburgh
Better than trying to rescue a heart damaged by a heart attack is to try to prevent one happening in the first place. And Edinburgh cardiologist Marc Dweck, has a new method for spotting heart attacks waiting to happen, as he explained to Chris Smith.
Marc - Yes, so at the moment when we assess these coronary arteries the easiest thing to look at are there any narrowings there. But what weíve learnt is that actually the majority of heart attacks appear to have started where there isnít really a narrowing at all and so we need new techniques that go beyond just looking for narrowings. Looking at the components of that plaque, looking at the activity of those plaques to get a better sense of which of the plaques that are causing a problem and who are the patients who are more at risk of having heart attack.
Chris - What are you doing then to get a clearer picture of whatís going on in the risky bits of the arteries? How are you trying to spot them?
Marc - So we have a new imaging technique called PET imaging. Essentially this is where we inject traces in the body that tell us the activity of diseases processes as itís occurring in the body. So we can start to look at the coronary arteries, to look at plaques and say right, this plaque is active, it is doing something at the moment. This is not a patient who has stable coronary artery disease, this is someone whose disease process is active. And our hypothesis is that if you identify the active people, youíre going to identify people that are at higher risk.
Chris - What do you inject people with?
Marc - Itís radioactive fluoride, I guess. Radioactive toothpaste effectively. This has actually been used for many years to look at bone. Weíre now using it to image calcification activity in the coronary arteries.
Chris - So does calcium go along with dodgy bits of artery that might have a heart attack risk then?
Marc - Actually, we think that the calcification process is a healing process. So you have lots of inflammation in the artery and then the body tries to heal it up by calcifying it. If we see the early stages of that calcium, then we know that thereís a nasty plaque there that the body is trying to heal but it hasnít healed it up yet.
Chris - And this injection of radioactive toothpaste, the radioactive fluoride, that can highlight those early stage lesions can it?
Marc - Yes, we have looked at this in great detail over the last couple of years with Cambridge University, as well as Edinburgh, and it looks like this fluoride is binding to the very early stages of the calcium. So we are very excited about it.
Chris - So if you did this test on somebody and you saw a patch of artery that flashed up very hot on you PET scan with your radioactive fluoride marker suggesting to you this is a plaque which is very rapidly evolving, it might be a heart attack risk, what are you going to do for that patient then? How would you manage them?
Marc - Yes, thatís an excellent question. I think thereís two kind of schools of thought on this. One is that right, if you see an active plaque, a nasty plaque, then maybe you can try and stabalise that particular plaque.
Chris - How? What do you mean by stabalise?
Marc - So people have thought about maybe trying to put a stent into that plaque to stop it from rupturing. To strengthen the wall of it, I guess. Personally, I donít believe thatís the right approach because what often happens is you see one active plaque at a moment in time but this is a dynamic process. That plaque might heal up OK, but another plaque may develop in another area and so, actually, I think the best chance of us preventing events is to use drugs. Things like statins, things like aspirin that kind of treat all the plaques at the same time and, in particular, we are developing very powerful drugs that really lower cholesterol levels a lot, but theyíre very expensive. And so we need to be able to target those drugs to the patients that are at the highest risk and so I think thatís the space where this kind of imagining technique may have a role where youíre really trying to identify those at the very highest risk that are going to benefit from the most aggressive expensive treatments.