Heart Disease UK

Computed tomography
Avijit Lahiri, Eric Lim & Vijay Anand
The recent introduction of cardiac CT (computed tomography) technology provides an exciting new advance. This technology is able to take accurate pictures of the heart from outside the body and, thereby, identity early heart disease; the test is pain – free and can be completed in minutes. With the latest scanners developed by such large multinational businesses as GE Healthcare, scan times are now being reduced to just a few seconds while the quality of images is nothing short astounding.
How do these test work? They work by taking a picture of the heart and identifying calcium deposits. For reasons that are not clear, as heart disease develops, fat (cholesterol) enters the wall of the coronary artery and provokes inflammation. As part of this process, the body sends specialist cells called macrophages to invade the wall of the artery. At the same time, calcium is dense and does not permit x- rays to pass through; these deposits can be visualized even in very minute amounts using cardiac CT.
Cardiac CT has now been shown to be robust technique. Recent studies by Dr Shaw and colleagues from the USA have shown that the more coronary artery calcium present, the higher the risk of death. This is a seminal trial, which has provided for the development for protocols for early investigation and research.
We ourselves have recently completed a trial in 510 diabetics. Although none of these patients had any signs or symptoms of coronary disease, nevertheless, 43 per cent of them where shown to have coronary artery calcium using electron beam CT scanning technology. Our initial data also appears to confirm that the amount of coronary artery calcium strongly predicts future cardiac events (death, heart attack, stroke and so on). Besides, the data clearly shows that prediction based on the scan result were superior to those based on the measurement of all other standard risk factors and biochemical tests. We went further by performing another test called myocardial perfusion imaging (with a so call radioactive tracer known as technetium sestamibi). This test told us that in patients with high coronary artery calcium scores, blockage of the arteries supplying the heart was very common in those with the symptom of chest pain.
The combination if the two tests were superior to either independently and allowed us to completely define the early management of disease in these patients. This trial adds further proof that “silent” heart disease is predominant in patients with diabetes and it’s early detection may not only improve the quality of the life but also save lives.