Screening for Coronary Artery Disease in Asymptomatic Diabetics: Can it be Done? Is it Useful?

Diabetics have more coronary artery disease (CAD) than non-diabetics and high prevalence of additional CAD risk factors. Risk factor based scores including duration of diabetes and glycemic control can stratify risk for CAD events in asymptomatic diabetics. Myocardial perfusion scintigraphy can stratify risk and the coronary artery calcium score provides additional prognostic information. Coronary CT angiography (CTA) characterizes coronary plaques and evaluates coronary stenosis.

Data presented will define the added value of CTA in an asymptomatic diabetic cohort in predicting outcomes in this population. However it remains unclear if preventive medical or interventional therapy for disease discovered on screening will improve outcomes over those obtained by current treatment of risk factors. In the DIAD study of asymptomatic diabetics on medical therapy many baseline myocardial perfusion defects were no longer present on follow-up scanning and provision of screening results to treating physicians did not improve overall outcomes. Similarly in the randomized FACTOR-64 trial of CT angiography in asymptomatic diabetics outcomes at 4 years were not improved following provision of screening results to treating physicians. On the other hand asymptomatic diabetics have diverse coronary findings from plaque-free arteries to diffuse 3 vessel disease. Many included in randomized studies were at very low risk and screening could not lead to improved event rates. Screening for CAD with CTA directed at subjects with worse risk factor profiles and higher CAC scores may prove to be more effective while providing reassurance to those with normal coronary arteries.

Useful prognostic information can be obtained in asymptomatic diabetics from a cohort screened with CT angiography however routine screening for coronary artery disease in asymptomatic diabetics in order to improve outcomes is not currently recommended.