FROM JAMA CARDIOLOGY
Younger adults who have any calcium deposited in their coronary arteries, even a small amount, are at increased risk for adverse coronary heart disease (CHD) outcomes and death, finds an analysis of the Coronary Artery Risk Development in Young Adults ( CARDIA ) Study.
There’s no evidence, however, that treating such patients would make a difference in outcomes, John Jeffrey Carr, MD , reported in JAMA Cardiology on Feb. 8.
In the prospective, community-based, cohort study, 5,115 black and white adults underwent coronary computed tomographic (CT) imaging between the ages of 32 and 46 years, and had a mean follow-up of 12.5 years.
Compared with counterparts not having any coronary artery calcium (CAC), those having at least some had a 5.0-fold increased risk of CHD events and a 1.6-fold increased risk of death ( JAMA Cardiol. 2017 Feb 8; doi: 10.1001/jamacardio.2016.5493 ).
Estimates suggested that identification of individuals at elevated risk for developing CAC could inform a selective CT screening strategy whereby the number of younger adults screened could be reduced by half, and the number needing to be imaged to find one person with CAC could be reduced from 3.5 to 2.2.
“The finding that CAC present by ages 32-46 years is associated with increased risk of premature CHD and death emphasizes the need for reduction of risk factors and primordial prevention beginning in early life,” wrote Dr. Carr, professor radiology at Vanderbilt University in Nashville, Tenn.
“Whether any kind of general screening for CAC is warranted needs further study, although we suggest that a strategy in which all individuals aged 32 to 46 years are screened is not indicated. Rather, a more targeted approach based on measuring risk factors in early adult life to predict individuals at high risk for developing CAC in whom the CT scan would have the greatest value can be considered,” they propose.
Study details
Participants were recruited to CARDIA when aged 18-30 years, and they underwent CAC measurement at 15, 20, and 25 years after recruitment. Incident events were ascertained starting from the time of the year-15 scan.
At that year-15 scan, 10.2% of participants were found to have CAC. The geometric mean Agatston score was 21.6.
In adjusted analyses, participants with any CAC had sharply higher risks of CHD events (hazard ratio, 5.0), as well as cardiovascular disease events (HR, 3.0). The risk of CHD events increased with CAC score, with hazard ratios of 2.6, 5.8, and 9.8 for individuals with scores of 1-19, 20-99, and 100 or more, respectively.
In addition, participants with any CAC had an elevated adjusted risk of all-cause mortality (HR, 1.6). This risk similarly rose with score but was significant for those having a score of 100 or greater only (hazard ratio, 3.7); the large majority of deaths in this group were deemed to be from CHD events.
The model that the investigators developed predicted the probability of CAC by ages 32-56 years based on risk factors assessed 7 years apart, between the ages of 18 and 38 years.
When stratified by this model, 4.2% of study participants falling into the lowest-risk decile had CAC, compared with 67.8% of those falling into the highest-risk decile.
Analyses suggested that if screening were restricted to those participants having an above-median risk score, fully 77.3% of all those with coronary calcium and 95.5% of all those with CHD events would be identified. Moreover, these yields would be obtained while reducing the number of individuals recommended to be screened by 50.0%.
