Obstructive CAD May Occur Without Coronary Artery Calcium in Young Adults

Among individuals aged younger than 60 years, a sizable proportion of obstructive coronary artery disease (CAD) occurred without the presence of coronary artery calcium (CAC). The findings, from a cohort study, were published in JAMA Cardiology.

Researchers sourced data from the Western Denmark Heart Registry. All adults (N=23,759) who underwent nonemergency computed tomography angiography due to symptoms of CAD between 2008 and 2017 were assessed for CAC and clinical outcomes.

The study population comprised 55% women; participants had a median age of 58 (interquartile range [IQR], 49-65) years; 21% were current smokers; 46% had hypertension; 27% used statins; and 58% had atypical chest pain.

Most individuals (54%) had a CAC score of 0. Among those without CAC, 6.0% had obstructive CAD. Stratified by age, the proportion of individuals with obstructive CAD was 3.0% among those aged less than 40 years, 5.0% for 40-49 years, 6.0% for 50-59 years, 6.0% for 60-69 years, and 8.0% for those aged 70 years and older.

The proportion of patients with obstructive CAD with a CAC score of 0 was 14%. The proportion of individuals with a score of 0 decreased with increasing age from 58% among those aged younger than 40 years, 34% for 40-49 years, 18% for 50-59 years, 9.0% for 60-69 years, and 5.0% for those aged 70 years and older. Women tended to have obstructive CAD with a CAC score of 0 more often than men.

The diagnostic likelihood ratio (DLR) of using a CAC score of 0 was 0.38±0.17 overall and was lowest among men aged 70 years and older (DLR, 0.13±0.02) and highest among women aged younger than 40 years (DLR, 0.82± 0.22).

During a median follow-up of 4.3 years, first-time myocardial infarction (MI) or all-cause deaths occurred among 774 study participants. Among these events, 31% occurred among individuals with a CAC score of 0 (4.31 events per 1000 person-years). Individuals who were aged younger than 60 years with obstructive CAD and a CAC score of 0 were at increased risk for MI or death (adjusted hazard ratio [aHR], 1.80; 95% CI, 1.02-3.19).

These findings may not be generalizable to a non-European population, as Europeans have been associated with a low CAD risk compared with other populations.

This study found that using a CAC score of 0 to rule out obstructive CAD may not be sufficient, especially among those aged younger than 60 years.

“These results may help to inform future guidelines on the differential value of CAC in the workup of patients with symptoms suggestive of CAD,” the study authors noted.

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.

Reference

Mortensen MB, Gaur S, Frimmer A, et al. Association of age with the diagnostic value of coronary artery calcium score for ruling out coronary stenosis in symptomatic patients. JAMA Cardiol. Published online October 27, 2021. doi:10.1001/jamacardio.2021.4406