Consider Coronary Artery Calcium: 7 Questions

Question 1. How much radiation exposure do patients receive from a CAC scan?

Question 2. What does the Agatston score assess?

Answer: C. Amount of calcium in the walls of the coronary arteries. The Agatston score is provided as an absolute number or as a percentile for age, sex and race/ethnicity.

Question 3. True or False: The CAC score has been shown to have a robust association with hard cardiac events (MI, cardiac death, resuscitated cardiac arrest) over 5 to 10 years of follow-up.

Answer: A. True. Analyses of the Multi-Ethnic Study of Atherosclerosis (MESA) and other epidemiologic studies have shown a robust association between CAC and risk of hard cardiac events (MI, cardiac death, resuscitated cardiac arrest).

Question 4. Which major concern has kept international guidelines from unanimously incorporating CAC testing into CV risk assessment?

Answer: C. Long-term outcomes may not be consistent with shorter-term outcomes associated with CAC scoring. The CAC scan is a 10-minute, non-invasive chest CT scan that assesses concentration of calcium in coronary artery walls, identifying hardened plaques. Unlike a coronary CTA, the CAC scan does not require contrast dye. The amount of calcium in the walls of the coronary arteries is assessed by the Agatston score, which is provided as an absolute number or as a percentile for age, sex and race/ethnicity.

Studies have shown that the CAC score is correlated with all-cause mortality with an incremental relationship. In addition, the 2013 ACC/AHA and 2016 Canadian Cardiovascular Society guidelines support its use in patients with intermediate risk in whom preventive treatment strategy is uncertain.

However, incorporation of the CAC score in current international guidelines is variable. A major concern is that the associated risk seen over shorter term follow-up may not fully translate to long-term follow-up.

Answer: A. When a risk-based treatment decision is uncertain. The ACC/AHA has a Class IIB recommendation when “a risk-based treatment decision is uncertain.” After quantitative risk scoring using traditional risk factors, CAC can be used to refine the risk estimate and lead to more informed shared decision making between patient and clinician on preventive therapy.

Question 6. CAC is strongly associated in a graded fashion with 10-yr risk of incident ASCVD in patients ____ lipid therapy.

Answer: C. … both on and off (lipid therapy). According to a study by Budoff et al utilizing the MESA cohort, CAC is strongly associated in a graded fashion with 10-year risk of incident ASCVD in patients both on and off lipid therapy.

Question 7. Which of the following is correct regarding the CAC score and ethnicity?

Answer: B. CAC is related to risk independent of ethnicity. There are multiple studies on the variation in CAC scores among ethnicities, but even after accounting for ethnicity, the CAC score is an independent risk predictor.