Coronary Artery Calcium Imaging for Risk Stratification

Striking advancements in cardiovascular diagnostics and therapeutics during the last several decades produced a marked decrease in mortality due to atherosclerotic diseases in western societies. Nonetheless, coronary artery disease (CAD) remains the main cause of death, being responsible for more deaths than all cancers combined, and it is associated with substantial functional impairment in survivors of acute events, imposing a very large economical burden on society. Numerous risk scores based on identifiable patients’ characteristics were developed to improve identification of patients at higher risk of events, to whom intensive preventive therapies should be directed. Nonetheless, most of these tools are incompletely effective, and the majority of events develop in subjects not considered to be at high risk. The attention of several investigators therefore turned to the development of imaging tools to identify atherosclerosis or its signature in its preclinical stages. Coronary artery calcium (CAC) imaging is one of the imaging tests that received the most attention in the past 20 years, and one that has raised a large controversy among field experts. That calcium deposition accompanies the formation of atherosclerotic plaque from its inception has been well-known for two centuries. More recently, it has become apparent that CAC deposition occurs via active processes of calcification resembling bone formation. Finally, the calcified portion represents approximately 15–20% of the total atheroma volume. In this chapter, we will review the most relevant literature on the use of CAC as a risk stratification tool of asymptomatic patients as well as the utility of sequential CAC scanning to follow the evolution of atherosclerosis.