Exploring the Complementary Role of CAC and Coronary CT in the Primary CVD Prevention Setting

Coronary artery calcification (CAC) imaging is widely used for the assessment of patients at moderate risk of cardiovascular disease. It is more logical and practical to detect preclinical coronary artery disease (CAD) rather than to make predictions based solely on risk factor assessment. Furthermore, CAC imaging leads to the reclassification of a significant proportion of moderate-risk patients into lower or higher risk categories. In higher-risk patients, including for example those with diabetes, a higher prevalence of CAC has been shown to be associated with a high short-term risk of cardiovascular events, while those with a zero calcium score have excellent event-free survival, similar to survival in nondiabetic patients. Having a zero calcium score is currently used in UK practice guidelines as a criterion for further investigations in patients presenting to emergency departments with chest pain. Unanswered questions include the concept of CAC progression that needs to be standardized with respect to technique, interpretation and subsequent management strategies. Recent studies have also demonstrated that risk assessment using CT is motivational to patients leading to better adherence to their preventive practices as well as medication. However, statin has not proved to be consistently beneficial in slowing the CAC progression rate, but does significantly reduce cardiovascular events in patients with increased CAC. Screening asymptomatic subjects to target measures for the prevention of cardiovascular events remains a major challenge. The established primary prevention risk-scoring methods use equations derived from large prospective cohort studies, but further fine-tuning of cardiovascular risk assessment remains important as 25 % of individuals with a low estimated risk may experience cardiac events. In this modern scientific world, the addition of CT is the best tool to add to the diagnostic work-up of CAD, as validated by multiple population-based studies and large-scale clinical trials.