Screening for Coronary Artery Disease Using CT Coronary Angiography, Coronary Artery Calcium Scoring and Myocardial Perfusion Imaging: A Review of Current Evidence of Potential Benefits and Risks

Screening for coronary artery disease (CAD), using CT coronary angiography, coronary artery calcium scoring and myocardial perfusion imaging, seems an attractive idea. However, there is considerable uncertainty whether the overall potential benefits outweigh the risks. In a situation where the prevalence of disease is very low, the positive predictive value of any test will tend to be low, and false positive results frequent, requiring a large number of individuals to undergo further testing to confirm disease in a small number of patients. Even when disease is detected, the benefits of revascularisation are uncertain in asymptomatic populations. There is considerable uncertainty about the risks from radiation as a result of imaging tests such as CT scans. Based on available data, the actual risks of malignancy for most individuals appear to be small and of limited concern in a symptomatic patient with a moderate likelihood of disease. However, in a low risk population as in the context of coronary artery screening, the likelihood of benefit is likely to be much smaller due to the lower likelihood of disease, and may well be balanced by the possibility of harm. Screening for CAD using CT coronary angiography, coronary artery calcium scoring and myocardial perfusion imaging should be undertaken only after all these limitations have been properly discussed with the patient, and the patient's global risk of CAD has been estimated using conventional risk scoring. Testing should not be undertaken without careful consideration of whether the test result might change the patient's risk category and plan of management.