The new imaging technique can be applied as a new feature in routine computed tomography angiography (CTA), and will improve the diagnosis and management of coronary artery disease, enabling timely prevention strategies and improving the treatment of thousands of people living with the disease.
The findings were published in Science Translational Medicine on 12 July.
Coronary artery disease occurs when atherosclerotic plaques build up in the arteries that serve the heart, causing the vessels to narrow. When they block without warning they lead to a heart attack.
Currently, diagnostic methods rely on detecting damage that has already been caused by these plaques – when the damage is irreversible and treatment options are often limited.
Inflammation is the local process preceding the development of these plaques, and is also the process that triggers rapid blockages leading to heart attacks. Therefore, detection of inflammation in the heart arteries has been an unmet need in cardiovascular diagnostics for more than 50 years.
The team led by Prof Charalambos Antoniades, Associate Professor of Cardiovascular Medicine at the University of Oxford, discovered a bidirectional communication between the heart arteries and the fat surrounding them. His team found that the fat surrounding these arteries ‘senses’ inflammation coming from the adjacent artery, resulting in altered fat composition.
A new imaging technology, based on routine CTA, called ‘perivascular fat attenuation indexing’ (FAI), tracks the changes in the fat surrounding inflamed arteries – even in the absence of visible plaques or narrowings.
The technology also detects ‘vulnerable’ plaques that are prone to sudden blockages, flagging the individuals at highest risk for heart attacks.
Identifying those individuals without narrowings, but with inflamed heart arteries, is expected to allow deployment of targeted preventive measures, early enough to prevent the development of heart disease.
Furthermore, detecting patients with established heart disease who have plaques that could lead to a heart attack will guide application of the new but expensive therapeutic interventions available, to those of the patients who really need them.
Professor Keith Channon, Director of the NIHR Oxford Biomedical Research Centre and one of the co-investigators of the study, said: “Developing methods that will enable clinicians to identify people whose vessels are in the early process of developing narrowings, and are at a high risk of causing a heart attack, has been a longstanding goal for research in cardiovascular disease.
“We’ve known that vascular inflammation drives both the earliest stages of coronary artery disease, and in the events directly preceding a heart attack, but until now we have had no way to easily detect inflammation in the coronary arteries. This new imaging technique can be applied to existing CT angiograms, without additional equipment, making it widely applicable.”
Professor Charalambos Antoniades, who leads the University of Oxford research team, said: “Currently, CT scans can only identify people who have significant narrowings in their heart vessels. But by then the disease may have already caused damage which cannot be undone, and it is not possible to identify which narrowings might progress to cause a heart attack.
“The new scan offers the potential to find people at an earlier stage of disease and before the damage becomes irreversible. By providing an early warning of disease, the new imaging technique can be used by doctors as the trigger for more powerful treatments designed to reduce the risk of a future heart attack.”
NIHR Oxford BRC Imaging Theme Lead, Prof Stefan Neubauer, said: “This method is likely to be a significant advance on the coronary calcium scoring that is currently used to assess risk, and it can be used in conjunction with it.
“It provides a way to detect early inflammatory changes while there is still room for preventative and disease-modifying actions to be implemented. In future, this method could guide therapeutic strategies for patients who have had a heart attack, and for those who have not. We are eagerly anticipating the results of an ongoing clinical study examining the ability of this method to predict cardiac death.”
Dr Nikant Sabharwal, Consultant Cardiologist at Oxford University Hospitals, added: “With this new technique, by detecting those individuals who don’t have vascular narrowings, but who are in the process of developing them, we may in future be able to deploy strategies targeting this process early enough to prevent coronary heart disease.
“Equally, applying this method to patients who have known coronary heart disease, we may be able to identify those at very high risk of a heart attack, allowing us to use more aggressive treatments with agents that we would currently not use as part of the routine clinical practice.”