CAC score may help predict ASCVD risk

Assessing a person’s coronary artery calcium (CAC) score led to a modest improvement in predicting the risk for primary atherosclerotic cardiovascular disease (ASCVD), according to an analysis of nontraditional cardiovascular risk markers.

Multivariable Cox models found that the CAC score, ankle-brachial index and family history of ASCVD were each independent predictors of ASCVD events.

Lead researcher Joseph Yeboah, MD, MS, of Wake Forest Baptist Health in Winston-Salem, N.C., and colleagues published their findings online in the Journal of the American College of Cardiology on Jan. 11.

In 2013, the American College of Cardiology and the American Heart Association released a risk prediction tool using pooled cohort equations to assess primary ASCVD. Guidelines from those organizations also suggested using additional markers such as low-density lipoprotein cholesterol, family history of premature ASCVD, high-sensitivity C-reactive protein levels, lifetime ASCVD risk, ankle-brachial index and CAC score.

In this study, the researchers evaluated 5,185 participants who enrolled in the MESA (Multi-Ethnic Study of Atherosclerosis) trial, a population-based cohort study of adults who did not have known cardiovascular disease at baseline. The participants were recruited from six areas: Baltimore; Chicago; Forsyth County, N.C.; Los Angeles county; northern Manhattan; and St. Paul, Minn.

This analysis was restricted to participants between 40 and 75 years old because data suggests they could benefit the most from receiving statin therapy. At baseline, clinicians collected information on cardiovascular risk factors from participants, including their current smoking status, medication use, resting blood pressure, body mass index and high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and total cholesterol. They also assessed whether they had diabetes or hypertension.

The mean age of participants was 61.2 years old, while 53.1 percent were female, 38 percent were white, 9.8 percent had diabetes and 13.6 percent were current smokers. The first examination occurred between July 2000 and August 2002.

After a mean follow-up of 10 years, there were 320 ASCVD events: 43.4 percent were MIs, 41.3 percent were fatal or nonfatal strokes and 15.3 percent were coronary heart disease-related death.

Although the researchers excluded participants who took statins at baseline, they said some were prescribed statins during the follow-up period, which may have effected their event rates. However, they noted that a sensitivity analysis found statin use did not significantly change their point estimates or conclusions. They added that the results may not be generalizable because the MESA cohort was not representative of the general population.

“The nontraditional risk factors resulted in varying degrees of improvement in discrimination and reclassification of risk, including no improvement,” they wrote. “Verification of our findings in other racial and ethnic groups, as well as in other patient cohorts, is needed. Confirmation of our findings in other cohorts should consider the utility and the cost-effectiveness of using these risk markers for improving ASCVD risk assessment. The promise seen with the CAC score requires further study.”