Mortensen MB, Gaur S, Frimmer A, et al. - Findings reveal the presence of a sizable proportion of obstructive coronary artery disease (CAD) in younger patients without coronary artery calcium (CAC).

• Using data from the Western Denmark Heart Registry, a total of 23,759 symptomatic patients with obstructive CAD were analyzed in this cohort study.

• Marked variation in the prevalence of a CAC score of 0 was evident according to age group.

• The prevalence ranged from 58% in patients who were younger than 40 years to 5% in those who were 70 years or older.

• Age was the factor on which relied the diagnostic value of a CAC score of 0 to rule out obstructive CAD beyond clinical variables.

• A small diagnostic value of a CAC score of 0 in younger patients but a greater value in older patients was observed.

• In those with a CAC score of 0, obstructive CAD existence was related to a multivariable adjusted hazard ratio of 1.51 for myocardial infarction and all-cause death.

• This hazard ratio differed from 1.80 in those who were younger than 60 years to 1.24 in those who were 60 years or older.