In an award-winning British Heart Foundation (BHF) research project, scientists from Edinburgh and Cambridge University have tested a new imaging method that could help improve how doctors predict a patient's risk of having a heart attack. The study, published in the Journal of the American College of Cardiology (JACC), is the first to demonstrate the potential of combining PET and CT scanning to capture images of the disease processes directly in the coronary arteries, which cause heart attacks.
They measured the amount of calcified or hardened plaques in over 100 people's coronary arteries by using a CT calcium score, a standard test commonly used to predict the risk of CHD. The test is not able to distinguish between older deposits of calcium and those that are actively building up.
To establish whether they could identify patients with active, ongoing calcification due to the potentially higher risk compared with those whose calcification has developed a long time ago, the researchers injected all patients with two tracers, i.e. special molecules that are visible on certain imaging scans, such s PET scans for instance. The tracers can be used for tracking substances, such as 18F-sodium fluoride (18F-NaF), a molecule taken up by cells in which active calcification is occurring.
The findings displayed an increased 18F-NaF activity in specific coronary artery plaques in patients who had many other high-risk markers of cardiovascular disease.
Leading author, Dr Marc Dweck, a BHF Clinical Research Fellow at the University of Edinburgh, commented:
"Predicting heart attacks is very difficult and the methods we've got now are good but not perfect. Our new technique holds a lot of promise as a means of improving heart attack prediction although further ongoing work is needed before it becomes routine clinical practice.
If we can identify patients at high risk of a heart attack earlier, we can then use intensive drug treatments, and perhaps procedures such as stents, to reduce the chances of them having a heart attack."
Dr Shannon Amoils, Research Advisor at the (BHF), added:
"For decades cardiologists have been looking for ways to detect the high-risk plaques found in coronary arteries that could rupture to cause a heart attack, but it's been difficult to develop a suitable imaging test that can focus in on these small vessels. This research is a technical tour de force as it allows us to assess active calcification happening right in the problem area - inside the wall of the coronary arteries and this active calcification may correlate with a higher risk of a heart attack."
The research is based on Dr Dweck's recent work using PET/CT that shed more light onto aortic stenosis, an aortic valve disease. Dr Dweck and his Edinburgh team also want to adapt this technique to predict the risk of stroke in patients.