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.

Avijit Lahiri, Eric Lim & Vijay D. Anand
What about the economic burden of such an imaging strategy? Since these scans are versatile and many patients can be imaged in the same day, the cost of the test can be relatively low when performed in large volumes ($200 – 300 in the West). Since patients who do not have coronary artery calcification have an excellent outcome (<0.5 percent death rate per year) in a five – year follow up (Shaw and colleagues), using this model, over 50 per cent of the patients with diabetes would then be sent for standard medical treatment, whereas those with higher amounts of coronary artery calcium would undergo further testing (such as myocardial perfusion imaging described earlier). Those with negative tests would then be treated aggressively medically (tablets and the like). However in those with positive tests, opening up the artery physically (so-called coronary angioplasty) or even surgery may be more appropriate. In symptomatic patients, it is possible that using that using these tests can be very coat-effective. For example, patients with chest pain are often investigated using a test called exercise stress testing followed by coronary angiography. In the U.K. (where Dr Lahiri practices), this would cost per patient over ₤1200. If instead CT scanning were used, followed by myocardial perfusion imaging, a back-of-the-envelope calculation shows that it is quite possible to lower the cost by as much as 50 per cent. This translates to over half a million pounds per 1,000 patients.
These developments in the area of early detection of coronary artery disease will be even more exciting once they can be linked to emerging new therapeutic regimes for heart disease. For example, in animal models, early trails by Dr Shaw and colleagues have shown that it may be possible to develop a “vaccine” against heart disease. In the future, this potent combination of technologies, namely, early detection and powerful treatments, may be able to stem the misery of heart disease associated with diabetes.

South Asians living in the United Kingdom (Indians, Pakistanis, Bangladeshis and Sri Lankans) have a higher premature death rate from coronary heart disease than the UK average.

The Cardiac Imaging and Research Centre in the Wellington Hospital a state-of-the-art heart scanning unit

By having a Heart-Scan you can determine whether or not you have heart disease long before you feel any symptoms.